Amphiphilic multi-arm copolymers and nanomaterials derived therefrom

ABSTRACT

The present invention relates to polymers, nanomaterials, and methods of making the same. Various embodiments provide an amphiphilic multi-arm copolymer. The copolymer includes a core unit and a plurality of amphiphilic block copolymer arms. Each block copolymer arm is substituted on the core unit. Each block copolymer arm includes at least one hydrophilic homopolymer subunit and at least one hydrophobic homopolymer subunit. In some examples, the copolymer can include a star-like or bottlebrush-like block copolymer, and can include a Janus copolymer. Various embodiments provide a nanomaterial. In some examples, the nanomaterial can include Janus nanomaterials, and can include nanoparticles, nanorods, or nanotubes. The nanomaterial includes the amphiphilic multi-arm copolymer and at least one inorganic precursor. The inorganic precursor can be coordinated to at least one homopolymer subunit of one of the amphiphilic block copolymer arms to form the nanomaterial. Various embodiments also provide methods of making the copolymer and the nanomaterial.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/189,800, filed on Jul. 25, 2011, which application is incorporatedherein by reference in its entirety.

STATEMENT OF GOVERNMENT SUPPORT

This invention was made with government support under Grant No.FA9550-09-1-0388 awarded by the United States Air Force. The governmenthas certain rights in the invention.

BACKGROUND OF THE INVENTION

Polymers encompass a large class of natural and synthetic materials witha wide variety of properties. The ability to vary the properties ofpolymers, including boiling point, melting point, viscosity, polarity,tacticity, chain length, morphology, crystallinity, and mechanicalcharacteristics, makes them useful in a variety of applications.

Nanotechnology is a rapidly advancing area of science. Nanostructuresand nanomaterials (e.g., nanoparticles, nanorods, nanowires, nanotubes,etc.) can serve as building blocks or additives for other materials andthey continue to receive considerable attention due to their intriguingand varied properties. Organometallic and organic solution phasesynthetic routes have enabled the synthesis of functional inorganicquantum dots and nanoparticles. These nanomaterials form the buildingblocks for new bottom-up approaches to materials assembly for manytechnological applications. Nanotechnology continues to find new anduseful application in the areas of optics, electronics, optoelectronics,magnetic technologies, sensory materials and devices, drug delivery, andbiotechnology.

SUMMARY OF THE INVENTION

The present invention relates to polymers, nanomaterials, and methods ofmaking the same. Various embodiments provide an amphiphilic multi-armcopolymer. The copolymer includes a core unit and a plurality ofamphiphilic block copolymer arms. Each block copolymer arm issubstituted on the core unit. Each block copolymer arm includes at leastone hydrophilic homopolymer subunit and at least one hydrophobichomopolymer subunit. In some examples, the copolymer can include astar-like or bottlebrush-like block copolymer. Various embodimentsprovide a nanomaterial. In some examples, the nanomaterial can includeJanus nanomaterials, and can include nanoparticles, nanorods, ornanotubes. The nanomaterial includes the amphiphilic multi-arm copolymerand at least one inorganic precursor. The inorganic precursor can becoordinated to at least one homopolymer subunit of one of theamphiphilic block copolymer arms to form the nanomaterial. Variousembodiments also provide methods of making the copolymer and thenanomaterial.

Various embodiments of the present invention provide certain advantagesover other polymers, nanomaterials, and methods of making the same, someof which are surprising and unexpected. In various embodiments, thecopolymers of the present invention can be used as a template tosynthesize a wider variety of nanomaterials than other strategies ofusing polymers. Some embodiments can be simpler and less expensive thanother polymers, nanomaterials, and methods of making the same. In someembodiments, the method of making polymers or nanomaterials is moreeasily and cost-effectively scalable than other techniques. In someexamples, the copolymers of the present invention can be more stable,more monodisperse, and more static than other copolymers. In someembodiments, the copolymers can form unimolecular micelles, and can actas nanoreactors to form nanomaterials when inorganic precursorcoordinating compounds are added. In some embodiments, the nanomaterialsof the present invention can have functionalized surfaces, includingmultifunctionalized surfaces; by first forming a copolymer that containsthe functionalization and next building the nano structure via additionof coordinating compound, the functionalized surfaces can be generatedat a fraction of the cost and complexity with which other functionalizednanomaterials are generated. In some embodiments, the size of thenanomaterials generated can be precisely tailored by adjusting thelength of the chain of polymer subunits to which the coordinatingcompounds associate; the size and monodispersity of the nanomaterials ofsome embodiments of the present invention can be easily and preciselycontrolled. In some embodiments, certain polymers can allow formation ofinorganic-core nanomaterials, inorganic-shell nanomaterials, ornanomaterials including an inorganic-core and an inorganic-shell. Insome examples of inorganic-shell nanomaterials, the inner-structuralaspects of the resulting nanomaterial can be independent of the outerstructural aspects that include the coordinating inorganic material;likewise, in some examples of nanomaterials with functionalizedsurfaces, the structural aspects of the functionalization can beindependent of the structural aspects of the inorganic-core; thus, someembodiments of the present invention can circumvent some of thelimitations of epitaxial growth. In some examples, for nanomaterialsincluding an inorganic-core or inorganic-shell, the thickness of theinorganic-core or inorganic-shell can be precisely and easily controlledby altering the length of the chain of polymer subunits to which theinorganic precursor material coordinates. In some examples, themonodispersity of the copolymers and nanomaterials can be high,including due to the use of living polymerization to form thecopolymers. In some examples, the approach of the present invention tosynthesis of polymers and nanomaterials therefrom is simple, robust, andgeneralizable, allowing synthesis of a wide range of functionalnanoparticles (including, for example, semiconducting, metallic,magnetic, ferroelectric, multiferroic, upconvering, ferroelectric, andthe like) and multifunctional inorganic-core/inorganic-shellnanoparticles (including, for example, fluorescent/plasmonic,magnetic/plasmonic, upconverting/fluorescent, ferroelectric/magnetic,and the like). In some embodiments, the copolymers and nanomaterials ofthe present invention can be Janus structures, including Janusnanoparticles, Janus nanorods, and Janus nansotubes. The copolymers andnanomaterials of the present invention can have novel and usefulproperties, and can be made at large scale and at affordable cost, whichcan provide for applications in areas where nanomaterials and copolymershave been traditionally used, as well as uses in new areas that werebefore not possible or known. In various embodiments, potential areas ofapplication include optical, nanoelectronic, optoelectronic,photovoltaic, magnetic, spintronic, sensory materials and devices,nanoreactors, catalysis, capacitors, actuators, transducers,superconductors, as well as nanotechnology, biotechnology and biomedicalapplications.

In various embodiments, the present invention provides an amphiphilicmulti-arm copolymer. The copolymer includes a core unit. The polymeralso includes a plurality of amphiphilic block copolymer arms. Eachblock copolymer arm is substituted on the core unit. Each blockcopolymer includes at least one hydrophilic homopolymer subunit and atleast one hydrophobic homopolymer subunit. In some embodiments, theamphiphilic multi-arm copolymer can act as a template for theconstruction of nanomaterials.

In various embodiments, the present invention provides a method ofmaking an amphiphilic multi-arm copolymer. The method includes providinga core that includes hydroxyl functional groups. The method includescontacting the core with a halogenated esterification reagent. Thecontacting gives a macro-initiator core that includes the core with atleast some of the hydroxyl functional groups esterified by thehalogenated esterification reagent. The method includes contacting themacro-initiator core with a first homopolymer subunit precursor. Thecontacting gives a first substituted core wherein the first substitutedcore includes the macro-initiator core wherein at least one halogen atomis replaced with a first homopolymer including subunits that include areaction product of the first homopolymer subunit precursor. The methodincludes contacting the first substituted core with a second homopolymersubunit precursor. The second homopolymer subunit precursor is differentthan the first homopolymer subunit precursor. The contacting gives asecond substituted core that includes the first substituted core whereinthe first homopolymer is substituted with a second homopolymer thatincludes subunits that include a reaction product of the secondhomopolymer subunit precursor.

In various embodiments, the present invention provides a method ofmaking a nanomaterial. The method includes contacting an amphiphilicmulti-arm copolymer provided by embodiments of the present inventionwith an inorganic precursor. The contact forms a nanomaterial thatincludes the amphiphilic multi-arm copolymer coordinated to theinorganic precursor.

In various embodiments, the present invention provides a method ofmaking a nanomaterial. The method includes the method of making anamphiphilic multi-arm copolymer. The method includes contacting theamphiphilic multi-arm copolymer with an inorganic precursor. Thecontacting forms a nanomaterial that includes the amphiphilic multi-armcopolymer coordinated to the inorganic precursor.

BRIEF DESCRIPTION OF THE FIGURES

In the drawings, which are not necessarily drawn to scale, like numeralsdescribe substantially similar components throughout the several views.Like numerals having different letter suffixes represent differentinstances of substantially similar components. The drawings illustrategenerally, by way of example, but not by way of limitation, variousembodiments discussed in the present document.

FIG. 1 illustrates the synthesis of a star-like PAA-b-PEO amphiphilicmulti-arm copolymer via a combination of ATRP and click chemistry.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to certain claims of the disclosedsubject matter, examples of which are illustrated in the accompanyingdrawings. While the disclosed subject matter will be described inconjunction with the enumerated claims, it will be understood that theyare not intended to limit the disclosed subject matter to those claims.On the contrary, the disclosed subject matter is intended to cover allalternatives, modifications, and equivalents, which can be includedwithin the scope of the presently disclosed subject matter as defined bythe claims.

References in the specification to “one embodiment”, “an embodiment”,“an example embodiment”, etc., indicate that the embodiment describedcan include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed.

In this document, the terms “a” or “an” are used to include one or morethan one and the term “or” is used to refer to a nonexclusive “or”unless otherwise indicated. In addition, it is to be understood that thephraseology or terminology employed herein, and not otherwise defined,is for the purpose of description only and not of limitation.Furthermore, all publications, patents, and patent documents referred toin this document are incorporated by reference herein in their entirety,as though individually incorporated by reference. In the event ofinconsistent usages between this document and those documents soincorporated by reference, the usage in the incorporated referenceshould be considered supplementary to that of this document; forirreconcilable inconsistencies, the usage in this document controls.

In the methods of manufacturing described herein, the steps can becarried out in any order without departing from the principles of theinvention, except when a temporal or operational sequence is explicitlyrecited. Recitation in a claim to the effect that first a step isperformed, then several other steps are subsequently performed, shall betaken to mean that the first step is performed before any of the othersteps, but the other steps can be performed in any suitable sequence,unless a sequence is further recited within the other steps. Forexample, claim elements that recite “Step A, Step B, Step C, Step D, andStep E” shall be construed to mean step A is carried out first, step Eis carried out last, and steps B, C, and D can be carried out in anysequence between steps A and E, and that the sequence still falls withinthe literal scope of the claimed process. A given step or sub-set ofsteps can also be repeated, or carried out simultaneously with othersteps.

Furthermore, specified steps can be carried out concurrently unlessexplicit claim language recites that they be carried out separately. Forexample, a claimed step of doing X and a claimed step of doing Y can beconducted simultaneously within a single operation, and the resultingprocess will fall within the literal scope of the claimed process.

DEFINITIONS

The singular forms “a,” “an” and “the” can include plural referentsunless the context clearly dictates otherwise.

The term “about” can allow for a degree of variability in a value orrange, for example, within 10%, or within 5% of a stated value or of astated limit of a range. When a range or a list of sequential values isgiven, unless otherwise specified any value within the range or anyvalue between the given sequential values is also disclosed.

The term “organic group” as used herein refers to but is not limited toany functional group that an organic chemist can envision, includinghalogen (i.e., F, Cl, Br, and I); an oxygen-containing group such ashydroxyl groups, alkoxy groups, aryloxy groups, aralkyloxy groups,oxo(carbonyl) groups, carboxyl groups including carboxylic acids,carboxylates, and carboxylate esters; a sulfur-containing group such asthiol groups, alkyl and aryl sulfide groups, sulfoxide groups, sulfonegroups, sulfonyl groups, and sulfonamide groups; a nitrogenatom-containing group such as amines, hydroxylamines, nitriles, nitrogroups, N-oxides, hydrazides, azides, and enamines; and otherheteroatom-containing groups. Non-limiting examples of organic groupsinclude F, Cl, Br, I, OR′, OC(O)N(R′)₂, CN, NO, NO₂, ONO₂, azido, CF₃,OCF₃, R′, O(oxo), S(thiono), C(O), S(O), methylenedioxy, ethylenedioxy,N(R′)₂, SW, SOW, SO₂R′, SO₂N(R′)₂, SO₃R′, C(O)R′, C(O)C(O)R′,C(O)CH₂C(O)R′, C(S)R′, C(O)OR′, OC(O)R′, C(O)N(R′)₂, OC(O)N(R′)₂,C(S)N(R′)₂, (CH₂)₀₋₂N(R′)C(O)R′, (CH₂)₀₋₂N(R′)N(R′)₂, N(R′)N(R′)C(O)R′,N(R′)N(R′)C(O)OR′, N(R′)N(R′)CON(R′)₂, N(R′)SO₂R′, N(R′)SO₂N(R′)₂,N(R′)C(O)OR′, N(R′)C(O)R′, N(R′)C(S)R′, N(R′)C(O)N(R′)₂,N(R′)C(S)N(R′)₂, N(COR′)COR′, N(OR′)R′, C(═NH)N(R′)₂, C(O)N(OR′)R′, orC(═NOR′)R′ wherein R′ can be hydrogen or a carbon-based moiety, andwherein the carbon-based moiety can itself be further substituted; forexample, wherein R′ can be hydrogen, alkyl, acyl, cycloalkyl, aryl,aralkyl, heterocyclyl, heteroaryl, or heteroarylalkyl, wherein anyalkyl, acyl, cycloalkyl, aryl, aralkyl, heterocyclyl, heteroaryl, orheteroarylalkyl, or R′ can be independently mono- or multi-substitutedwith J; or wherein two R′ groups bonded to a nitrogen atom or toadjacent nitrogen atoms can together with the nitrogen atom or atomsform a heterocyclyl, which can be mono- or independentlymulti-substituted with J. Examples of organic groups include linearand/or branched groups such as alkyl groups, fully or partiallyhalogen-substituted haloalkyl groups, alkenyl groups, alkynyl groups,aromatic groups, acrylate functional groups, and methacrylate functionalgroups; and other organic functional groups such as ether groups,cyanate ester groups, ester groups, carboxylate salt groups, mercaptogroups, sulfide groups, azide groups, phosphonate groups, phosphinegroups, masked isocyano groups, and hydroxyl groups. Examples of organicgroups include, but are not limited to, alkyl groups such as methyl,ethyl, propyl, isopropyl, n-butyl, s-butyl, and t-butyl groups, acrylatefunctional groups such as acryloyloxypropyl groups andmethacryloyloxypropyl groups; alkenyl groups such as vinyl, allyl, andbutenyl groups; alkynyl groups such as ethynyl and propynyl groups;aromatic groups such as phenyl, tolyl, and xylyl groups; cyanoalkylgroups such as cyanoethyl and cyanopropyl groups; halogenatedhydrocarbon groups such as 3,3,3-trifluoropropyl, 3-chloropropyl,dichlorophenyl, and 6,6,6,5,5,4,4,3,3-nonafluorohexyl groups;alkenyloxypoly(oxyalkyene) groups such as allyloxy(polyoxyethylene),allyloxypoly(oxypropylene), andallyloxy-poly(oxypropylene)-co-poly(oxyethylene) groups;alkyloxypoly(oxyalkyene) groups such as propyloxy(polyoxyethylene),propyloxypoly(oxypropylene), andpropyloxy-poly(oxypropylene)-co-poly(oxyethylene) groups;halogen-substituted alkyloxypoly(oxyalkyene) groups such asperfluoropropyloxy(polyoxyethylene),perfluoropropyloxypoly(oxypropylene), andperfluoropropyloxy-poly(oxypropylene)-co-poly(oxyethylene) groups;alkoxy groups such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy,and ethylhexyloxy groups; aminoalkyl groups such as 3-aminopropyl,6-aminohexyl, 11-aminoundecyl, 3-(N-allylamino)propyl,N-(2-aminoethyl)-3-aminopropyl, N-(2-aminoethyl)-3-aminoisobutyl,p-aminophenyl, 2-ethylpyridine, and 3-propylpyrrole groups; epoxyalkylgroups such as 3-glycidoxypropyl, 2-(3,4,-epoxycyclohexyl)ethyl, and5,6-epoxyhexyl groups; ester functional groups such as actetoxyethyl andbenzoyloxypropyl groups; hydroxy functional groups such as hydroxy and2-hydroxyethyl groups; masked isocyanate functional groups such aspropyl-t-butylcarbamate, and propylethylcarbamate groups; aldehydefunctional groups such as undecanal and butyraldehyde groups; anhydridefunctional groups such as 3-propyl succinic anhydride and 3-propylmaleic anhydride groups; and metal salts of carboxylic acids such as thezinc, sodium, or potassium salts of 3-carboxypropyl and 2-carboxyethyl.

The term “substituted” as used herein refers to an organic group asdefined herein in which one or more bonds to a hydrogen atom containedtherein are replaced by one or more bonds to a non-hydrogen atom suchas, but not limited to, a halogen (i.e., F, Cl, Br, and I); an oxygenatom in groups such as hydroxyl groups, alkoxy groups, aryloxy groups,aralkyloxy groups, oxo(carbonyl) groups, carboxyl groups includingcarboxylic acids, carboxylates, and carboxylate esters; a sulfur atom ingroups such as thiol groups, alkyl and aryl sulfide groups, sulfoxidegroups, sulfone groups, sulfonyl groups, and sulfonamide groups; anitrogen atom in groups such as amines, hydroxylamines, nitriles, nitrogroups, N-oxides, hydrazides, azides, and enamines; and otherheteroatoms in various other groups. Non-limiting examples ofsubstituents J that can be bonded to a substituted carbon (or other)atom include F, Cl, Br, I, OR′, OC(O)N(R′)2, CN, NO, NO2, ONO2, azido,CF3, OCF3, R′, O(oxo), S(thiono), C(O), S(O), methylenedioxy,ethylenedioxy, N(R′)2, SW, SOW, SO2R′, SO2N(R′)2, SO3R′, C(O)R′,C(O)C(O)R′, C(O)CH2C(O)R′, C(S)R′, C(O)OR′, OC(O)R′, C(O)N(R′)2,OC(O)N(R′)2, C(S)N(R′)2, (CH2)0-2N(R′)C(O)R′, (CH2)0-2N(R′)N(R′)₂,N(R′)N(R′)C(O)R′, N(R′)N(R′)C(O)OR′, N(R′)N(R′)CON(R′)2, N(R′)SO2R′,N(R′)SO2N(R′)2, N(R′)C(O)OR′, N(R′)C(O)R′, N(R′)C(S)R′, N(R′)C(O)N(R′)2,N(R′)C(S)N(R′)2, N(COR′)COR′, N(OR′)R′, C(═NH)N(R′)2, C(O)N(OR′)R′, orC(═NOR′)R′ wherein R′ can be hydrogen or a carbon-based moiety, andwherein the carbon-based moiety can itself be further substituted; forexample, wherein R′ can be hydrogen, alkyl, acyl, cycloalkyl, aryl,aralkyl, heterocyclyl, heteroaryl, or heteroarylalkyl, wherein anyalkyl, acyl, cycloalkyl, aryl, aralkyl, heterocyclyl, heteroaryl, orheteroarylalkyl or R′ can be independently mono- or multi-substitutedwith J; or wherein two R′ groups bonded to a nitrogen atom or toadjacent nitrogen atoms can together with the nitrogen atom or atomsform a heterocyclyl, which can be mono- or independentlymulti-substituted with J.

The term “alkyl” as used herein refers to straight chain and branchedalkyl groups and cycloalkyl groups having from 1 to about 20 carbonatoms, and typically from 1 to 12 carbons or, in some embodiments, from1 to 8 carbon atoms. Examples of straight chain alkyl groups includethose with from 1 to 8 carbon atoms such as methyl, ethyl, n-propyl,n-butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl groups. Examples ofbranched alkyl groups include, but are not limited to, isopropyl,iso-butyl, sec-butyl, t-butyl, neopentyl, isopentyl, and2,2-dimethylpropyl groups. As used herein, the term “alkyl” encompassesn-alkyl, isoalkyl, and anteisoalkyl groups as well as other branchedchain forms of alkyl. Representative substituted alkyl groups can besubstituted one or more times with any of the groups listed herein, forexample, amino, hydroxy, cyano, carboxy, nitro, thio, alkoxy, andhalogen groups.

The term “alkenyl” as used herein refers to straight and branched chainand cyclic alkyl groups as defined herein, except that at least onedouble bond exists between two carbon atoms. Thus, alkenyl groups havefrom 2 to about 20 carbon atoms, and typically from 2 to 12 carbons or,in some embodiments, from 2 to 8 carbon atoms. Examples include, but arenot limited to

vinyl, —CH═CH(CH₃), —CH═C(CH₃)₂, —C(CH₃)═CH₂, —C(CH₃)═CH(CH₃),—C(CH₂CH3)=CH2, cyclohexenyl, cyclopentenyl, cyclohexadienyl,butadienyl, pentadienyl, and hexadienyl among others.

The term “alkynyl” as used herein refers to straight and branched chainalkyl groups, except that at least one triple bond exists between twocarbon atoms. Thus, alkynyl groups have from 2 to about 20 carbon atoms,and typically from 2 to 12 carbons or, in some embodiments, from 2 to 8carbon atoms. Examples include, but are not limited to —C≡CH, —C≡C(CH3),—C≡C(CH2CH3), —CH2CCH, —CH2C≡C(CH3), and —CH2C≡C(CH2CH3) among others.

The term “acyl” as used herein refers to a group containing a carbonylmoiety wherein the group is bonded via the carbonyl carbon atom. Thecarbonyl carbon atom is also bonded to another carbon atom, which can bepart of an alkyl, aryl, aralkyl cycloalkyl, cycloalkylalkyl,heterocyclyl, heterocyclylalkyl, heteroaryl, heteroarylalkyl group orthe like. In the special case wherein the carbonyl carbon atom is bondedto a hydrogen, the group is a “formyl” group, an acyl group as the termis defined herein. An acyl group can include 0 to about 12-20 additionalcarbon atoms bonded to the carbonyl group. An acyl group can includedouble or triple bonds within the meaning herein. An acryloyl group isan example of an acyl group. An acyl group can also include heteroatomswithin the meaning here. A nicotinoyl group (pyridyl-3-carbonyl) groupis an example of an acyl group within the meaning herein. Other examplesinclude acetyl, benzoyl, phenylacetyl, pyridylacetyl, cinnamoyl, andacryloyl groups and the like. When the group containing the carbon atomthat is bonded to the carbonyl carbon atom contains a halogen, the groupis termed a “haloacyl” group. An example is a trifluoroacetyl group.

The term “cycloalkyl” as used herein refers to cyclic alkyl groups suchas, but not limited to, cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, and cyclooctyl groups. In some embodiments, thecycloalkyl group can have 3 to about 8-12 ring members, whereas in otherembodiments the number of ring carbon atoms range from 3 to 4, 5, 6, or7. Cycloalkyl groups further include polycyclic cycloalkyl groups suchas, but not limited to, norbornyl, adamantyl, bornyl, camphenyl,isocamphenyl, and carenyl groups, and fused rings such as, but notlimited to, decalinyl, and the like. Cycloalkyl groups also includerings that are substituted with straight or branched chain alkyl groupsas defined herein. Representative substituted cycloalkyl groups can bemono-substituted or substituted more than once, such as, but not limitedto, 2,2-, 2,3-, 2,4-2,5- or 2,6-disubstituted cyclohexyl groups ormono-, di- or tri-substituted norbornyl or cycloheptyl groups, which canbe substituted with, for example, amino, hydroxy, cyano, carboxy, nitro,thio, alkoxy, and halogen groups. The term “cycloalkenyl” alone or incombination denotes a cyclic alkenyl group.

The term “aryl” as used herein refers to cyclic aromatic hydrocarbonsthat do not contain heteroatoms in the ring. Thus aryl groups include,but are not limited to, phenyl, azulenyl, heptalenyl, biphenyl,indacenyl, fluorenyl, phenanthrenyl, triphenylenyl, pyrenyl,naphthacenyl, chrysenyl, biphenylenyl, anthracenyl, and naphthyl groups.In some embodiments, aryl groups contain about 6 to about 14 carbons inthe ring portions of the groups. Aryl groups can be unsubstituted orsubstituted, as defined herein. Representative substituted aryl groupscan be mono-substituted or substituted more than once, such as, but notlimited to, 2-, 3-, 4-, 5-, or 6-substituted phenyl or 2-8 substitutednaphthyl groups, which can be substituted with carbon or non-carbongroups such as those listed herein

The term “aralkyl” as used herein refers to alkyl groups as definedherein in which a hydrogen or carbon bond of an alkyl group is replacedwith a bond to an aryl group as defined herein. Representative aralkylgroups include benzyl and phenylethyl groups and fused(cycloalkylaryl)alkyl groups such as 4-ethyl-indanyl. Aralkenyl groupare alkenyl groups as defined herein in which a hydrogen or carbon bondof an alkyl group is replaced with a bond to an aryl group as definedherein.

The term “heterocyclyl” as used herein refers to aromatic andnon-aromatic ring compounds containing 3 or more ring members, of which,one or more is a heteroatom such as, but not limited to, N, O, and S.Thus a heterocyclyl can be a cycloheteroalkyl, or a heteroaryl, or ifpolycyclic, any combination thereof. In some embodiments, heterocyclylgroups include 3 to about 20 ring members, whereas other such groupshave 3 to about 15 ring members. A heterocyclyl group designated as aC₂-heterocyclyl can be a 5-ring with two carbon atoms and threeheteroatoms, a 6-ring with two carbon atoms and four heteroatoms and soforth. Likewise a C₄-heterocyclyl can be a 5-ring with one heteroatom, a6-ring with two heteroatoms, and so forth. The number of carbon atomsplus the number of heteroatoms sums up to equal the total number of ringatoms. A heterocyclyl ring can also include one or more double bonds. Aheteroaryl ring is an embodiment of a heterocyclyl group. The phrase“heterocyclyl group” includes fused ring species including those thatinclude fused aromatic and non-aromatic groups. For example, adioxolanyl ring and a benzdioxolanyl ring system (methylenedioxyphenylring system) are both heterocyclyl groups within the meaning herein. Thephrase also includes polycyclic ring systems containing a heteroatomsuch as, but not limited to, quinuclidyl. Heterocyclyl groups can beunsubstituted, or can be substituted as discussed herein. Heterocyclylgroups include, but are not limited to, pyrrolidinyl, piperidinyl,piperazinyl, morpholinyl, pyrrolyl, pyrazolyl, triazolyl, tetrazolyl,oxazolyl, isoxazolyl, thiazolyl, pyridinyl, thiophenyl, benzothiophenyl,benzofuranyl, dihydrobenzofuranyl, indolyl, dihydroindolyl, azaindolyl,indazolyl, benzimidazolyl, azabenzimidazolyl, benzoxazolyl,benzothiazolyl, benzothiadiazolyl, imidazopyridinyl, isoxazolopyridinyl,thianaphthalenyl, purinyl, xanthinyl, adeninyl, guaninyl, quinolinyl,isoquinolinyl, tetrahydroquinolinyl, quinoxalinyl, and quinazolinylgroups. Representative substituted heterocyclyl groups can bemono-substituted or substituted more than once, such as, but not limitedto, piperidinyl or quinolinyl groups, which are 2-, 3-, 4-, 5-, or6-substituted, or disubstituted with groups such as those listed herein.

The term “heteroaryl” as used herein refers to aromatic ring compoundscontaining 5 or more ring members, of which, one or more is a heteroatomsuch as, but not limited to, N, O, and S; for instance, heteroaryl ringscan have 5 to about 8-12 ring members. A heteroaryl group is a varietyof a heterocyclyl group that possesses an aromatic electronic structure.A heteroaryl group designated as a C₂-heteroaryl can be a 5-ring withtwo carbon atoms and three heteroatoms, a 6-ring with two carbon atomsand four heteroatoms and so forth. Likewise a C₄-heteroaryl can be a5-ring with one heteroatom, a 6-ring with two heteroatoms, and so forth.The number of carbon atoms plus the number of heteroatoms sums up toequal the total number of ring atoms. Heteroaryl groups include, but arenot limited to, groups such as pyrrolyl, pyrazolyl, triazolyl,tetrazolyl, oxazolyl, isoxazolyl, thiazolyl, pyridinyl, thiophenyl,benzothiophenyl, benzofuranyl, indolyl, azaindolyl, indazolyl,benzimidazolyl, azabenzimidazolyl, benzoxazolyl, benzothiazolyl,benzothiadiazolyl, imidazopyridinyl, isoxazolopyridinyl,thianaphthalenyl, purinyl, xanthinyl, adeninyl, guaninyl, quinolinyl,isoquinolinyl, tetrahydroquinolinyl, quinoxalinyl, and quinazolinylgroups. Heteroaryl groups can be unsubstituted, or can be substitutedwith groups as is discussed herein. Representative substitutedheteroaryl groups can be substituted one or more times with groups suchas those listed herein.

Additional examples of aryl and heteroaryl groups include but are notlimited to phenyl, biphenyl, indenyl, naphthyl(1-naphthyl, 2-naphthyl),N-hydroxytetrazolyl, N-hydroxytriazolyl, N-hydroxyimidazolyl,anthracenyl(1-anthracenyl, 2-anthracenyl, 3-anthracenyl),thiophenyl(2-thienyl, 3-thienyl), furyl(2-furyl, 3-furyl), indolyl,oxadiazolyl, isoxazolyl, quinazolinyl, fluorenyl, xanthenyl, isoindanyl,benzhydryl, acridinyl, thiazolyl, pyrrolyl(2-pyrrolyl),pyrazolyl(3-pyrazolyl), imidazolyl(1-imidazolyl, 2-imidazolyl,4-imidazolyl, 5-imidazolyl), triazolyl(1,2,3-triazol-1-yl,1,2,3-triazol-2-yl-1,2,3-triazol-4-yl, 1,2,4-triazol-3-yl),oxazolyl(2-oxazolyl, 4-oxazolyl, 5-oxazolyl), thiazolyl(2-thiazolyl,4-thiazolyl, 5-thiazolyl), pyridyl(2-pyridyl, 3-pyridyl, 4-pyridyl),pyrimidinyl(2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl, 6-pyrimidinyl),pyrazinyl, pyridazinyl(3-pyridazinyl, 4-pyridazinyl, 5-pyridazinyl),quinolyl(2-quinolyl, 3-quinolyl, 4-quinolyl, 5-quinolyl, 6-quinolyl,7-quinolyl, 8-quinolyl), isoquinolyl(1-isoquinolyl, 3-isoquinolyl,4-isoquinolyl, 5-isoquinolyl, 6-isoquinolyl, 7-isoquinolyl,8-isoquinolyl), benzo[b]furanyl(2-benzo[b]furanyl, 3-benzo[b]furanyl,4-benzo[b]furanyl, 5-benzo[b]furanyl, 6-benzo[b]furanyl,7-benzo[b]furanyl),2,3-dihydro-benzo[b]furanyl(2-(2,3-dihydro-benzo[b]furanyl),3-(2,3-dihydro-benzo[b]furanyl), 4-(2,3-dihydro-benzo[b]furanyl),5-(2,3-dihydro-benzo[b]furanyl), 6-(2,3-dihydro-benzo[b]furanyl),7-(2,3-dihydro-benzo[b]furanyl),benzo[b]thiophenyl(2-benzo[b]thiophenyl, 3-benzo[b]thiophenyl,4-benzo[b]thiophenyl, 5-benzo[b]thiophenyl, 6-benzo[b]thiophenyl,7-benzo[b]thiophenyl), 2,3-dihydro-benzo[b]thiophenyl,(2-(2,3-dihydro-benzo[b]thiophenyl), 3-(2,3-dihydro-benzo[b]thiophenyl),4-(2,3-dihydro-benzo[b]thiophenyl), 5-(2,3-dihydro-benzo[b]thiophenyl),6-(2,3-dihydro-benzo[b]thiophenyl), 7-(2,3-dihydro-benzo[b]thiophenyl),indolyl(1-indolyl, 2-indolyl, 3-indolyl, 4-indolyl, 5-indolyl,6-indolyl, 7-indolyl), indazole (1-indazolyl, 3-indazolyl, 4-indazolyl,5-indazolyl, 6-indazolyl, 7-indazolyl), benzimidazolyl(1-benzimidazolyl,2-benzimidazolyl, 4-benzimidazolyl, 5-benzimidazolyl, 6-benzimidazolyl,7-benzimidazolyl, 8-benzimidazolyl), benzoxazolyl(1-benzoxazolyl,2-benzoxazolyl), benzothiazolyl(1-benzothiazolyl, 2-benzothiazolyl,4-benzothiazolyl, 5-benzothiazolyl, 6-benzothiazolyl, 7-benzothiazolyl),carbazolyl(1-carbazolyl, 2-carbazolyl, 3-carbazolyl, 4-carbazolyl),5H-dibenz[b,f]azepine (5H-dibenz[b,f]azepin-1-yl,5H-dibenz[b,f]azepine-2-yl, 5H-dibenz[b,f]azepine-3-yl,5H-dibenz[b,f]azepine-4-yl, 5H-dibenz[b,f]azepine-5-yl),10,11-dihydro-5H-dibenz[b,f]azepine(10,11-dihydro-5H-dibenz[b,f]azepine-1-yl,10,11-dihydro-5H-dibenz[b,f]azepine-2-yl,10,11-dihydro-5H-dibenz[b,f]azepine-3-yl,10,11-dihydro-5H-dibenz[b,f]azepine-4-yl,10,11-dihydro-5H-dibenz[b,f]azepine-5-yl), and the like.

The term “heterocyclylalkyl” as used herein refers to alkyl groups asdefined herein in which a hydrogen or carbon bond of an alkyl group asdefined herein is replaced with a bond to a heterocyclyl group asdefined herein. Representative heterocyclyl alkyl groups include, butare not limited to, furan-2-yl methyl, furan-3-yl methyl, pyridine-3-ylmethyl, tetrahydrofuran-2-yl ethyl, and indol-2-yl propyl.

The term “heteroarylalkyl” as used herein refers to alkyl groups asdefined herein in which a hydrogen or carbon bond of an alkyl group isreplaced with a bond to a heteroaryl group as defined herein.

The term “alkoxy” as used herein refers to an oxygen atom connected toan alkyl group, including a cycloalkyl group, as are defined herein.Examples of linear alkoxy groups include but are not limited to methoxy,ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, and the like. Examples ofbranched alkoxy include but are not limited to isopropoxy, sec-butoxy,tert-butoxy, isopentyloxy, isohexyloxy, and the like. Examples of cyclicalkoxy include but are not limited to cyclopropyloxy, cyclobutyloxy,cyclopentyloxy, cyclohexyloxy, and the like. An alkoxy group can includeone to about 12-20 carbon atoms bonded to the oxygen atom, and canfurther include double or triple bonds, and can also includeheteroatoms. For example, an allyloxy group is an alkoxy group withinthe meaning herein. A methoxyethoxy group is also an alkoxy group withinthe meaning herein, as is a methylenedioxy group in a context where twoadjacent atoms of a structures are substituted therewith.

The term “amine” as used herein refers to primary, secondary, andtertiary amines having, e.g., the formula N(group)₃ wherein each groupcan independently be H or non-H, such as alkyl, aryl, and the like.Amines include but are not limited to R—NH₂, for example, alkylamines,arylamines, alkylarylamines; R₂NH wherein each R is independentlyselected, such as dialkylamines, diarylamines, aralkylamines,heterocyclylamines and the like; and R₃N wherein each R is independentlyselected, such as trialkylamines, dialkylarylamines, alkyldiarylamines,triarylamines, and the like. The term “amine” also includes ammoniumions as used herein.

The term “amino group” as used herein refers to a substituent of theform —NH₂, —NHR, —NR₂, —NR₃ ⁺, wherein each R is independently selected,and protonated forms of each, except for —NR₃ ⁺, which cannot beprotonated. Accordingly, any compound substituted with an amino groupcan be viewed as an amine. An “amino group” within the meaning hereincan be a primary, secondary, tertiary or quaternary amino group. An“alkylamino” group includes a monoalkylamino, dialkylamino, andtrialkylamino group.

The terms “halo” or “halogen” or “halide”, as used herein, by themselvesor as part of another substituent mean, unless otherwise stated, afluorine, chlorine, bromine, or iodine atom, preferably, fluorine,chlorine, or bromine.

The term “haloalkyl” group, as used herein, includes mono-halo alkylgroups, poly-halo alkyl groups wherein all halo atoms can be the same ordifferent, and per-halo alkyl groups, wherein all hydrogen atoms arereplaced by halogen atoms, such as fluoro. Examples of haloalkyl includetrifluoromethyl, 1,1-dichloroethyl, 1,2-dichloroethyl,1,3-dibromo-3,3-difluoropropyl, perfluorobutyl, and the like.

The term “hydrocarbon” as used herein refers to an organic group ormolecule that includes carbon and hydrogen atoms. The term can alsorefer to an organic group or molecule that normally includes both carbonand hydrogen atoms but wherein all the hydrogen atoms are substitutedwith other organic groups.

The term “solvent” as used herein refers to a liquid that can dissolve asolid, liquid, or gas. Nonlimiting examples of solvents are silicones,organic compounds, water, alcohols, ionic liquids, and supercriticalfluids.

The term “independently selected from” as used herein refers toreferenced groups being the same, different, or a mixture thereof,unless the context clearly indicates otherwise. Thus, under thisdefinition, the phrase “X¹, X², and X³ are independently selected fromnoble gases” would include the scenario where, for example, X¹, X², andX³ are all the same, where X¹, X², and X³ are all different, where X¹and X² are the same but X³ is different, and other analogouspermutations.

The term “amphiphilic” as used herein refers to a chemical compoundpossessing both hydrophilic and hydrophobic characteristics.

The term “molecule” as used herein refers to at least two atoms heldtogether via chemical bonds, including ionic, covalent, or coordinationbonds. In the present invention, the association of the inorganicprecursor and the amphiphilic copolymer in the nanomaterial isconsidered to be a chemical bond, such that the complex of the inorganicprecursor and the amphiphilic copolymer in the nanomaterial is amolecule.

The term “living polymerization” as used herein refers to a form ofpolymerization where the ability of growing polymer chain to terminatehas been removed. In living polymerization, chain termination and chaintransfer reactions are absent and the rate of chain initiation is alsomuch larger than the rate of chain propagation. As a result, the polymerchains can grow at a more constant rate than seen in traditional chainpolymerization and have a very low polydispersity index (e.g., theirlengths remain very similar). Living polymerization is widely used tosynthesize block copolymers since the polymer can be synthesized instages, each stage containing a different monomer. Additional advantagesinclude predetermined molar mass and control over end-groups. Livingpolymerization can be accomplished using a variety of methods, forexample, atom-transfer radical polymerization (ATRP), reversibleaddition-fragmentation chain transfer polymerization (RAFT), anionicpolymerization, coordination-insertion ring-opening polymerization, andthe like.

The term “click chemistry” as used herein refers to chemistry tailoredto generate substances quickly and reliably by joining small unitstogether. The reactions in click chemistry generally give high chemicalyields, and generally generate inoffensive byproducts. Click chemistrycan have simple reaction conditions, use readily available startingmaterials and reagents, use no solvent or use a solvent that is benignor easily removed (such as water), and can provide simple productisolation by non-chromatographic methods (e.g. crystallization ordistillation).

The term “copolymer” as used herein refers to a polymer derived from two(or more) monomeric species, as opposed to homopolymer where only onemonomer is used. A copolymer can include sections that are homopolymers.Copolymerization can refer to methods used to chemically synthesized acopolymer.

The term “homopolymer” as used herein refers to a polymer derived fromone monomeric species.

DESCRIPTION

The present invention relates to polymers, nanomaterials, and methods ofmaking the same. Various embodiments provide an amphiphilic multi-armcopolymer. The copolymer includes a core unit (e.g. macro-initiator) anda plurality of amphiphilic block copolymer arms. Each block copolymerarm is substituted on the core unit. Each block copolymer arm includesat least one hydrophilic homopolymer subunit and at least onehydrophobic homopolymer subunit. In some examples, the copolymer caninclude a star-like or bottlebrush-like block copolymer. Variousembodiments provide a nanomaterial. The amphiphilic multi-arm copolymercan serve as a template for making the nanomaterial. In some examples,the nanomaterial can include Janus nanomaterials, and can includenanoparticles, nanorods, or nanotubes. The nanomaterial includes theamphiphilic multi-arm copolymer template and at least one inorganicprecursor. The inorganic precursor can be coordinated to at least onehomopolymer subunit of one of the amphiphilic block copolymer arms toform the nanomaterial. Various embodiments also provide methods ofmaking the copolymer and the nanomaterial.

Amphiphilic Multi-Arm Copolymer

Various embodiments of the present invention provide an amphiphilicmulti-arm copolymer. The copolymer includes a core unit. The copolymeralso includes a plurality of amphiphilic block copolymer arms. Eachblock copolymer arm is substituted on the core unit. Each blockcopolymer includes at least one hydrophilic homopolymer subunit and atleast one hydrophobic homopolymer subunit. In some embodiments, theamphiphilic multi-arm copolymer can serve as a template for theformation of nanomaterials.

The core unit can be any appropriate core unit. The core unit can be asingle molecule. The core unit can be a large molecule that includesseveral smaller molecules linked together. The core unit can include anysuitable number of locations that can be substituted by the amphiphilicblock copolymer arms. In some examples, the core unit includes about 1,2, 3, 4, 5, 10, 20, 30, 40, or about 50 or more locations that can besubstituted with arms. In the copolymer, the core can be substituted atone of the substitutable locations, at all of the substitutablelocations, or at any number of the substitutable locations, with theamphiphilic block copolymer arms. In a given molecule of the amphiphilicmulti-arm copolymer, the copolymer can include core units that havecopolymer-substitutable locations, wherein some of the substitutablelocations are substituted by other moieties, wherein some of thesubstitutable locations are not substituted by any substituent, orwherein all of the substitutable locations are substituted by anamphiphilic block copolymer. The copolymer can include core units thatare substituted at some substitutable locations with an amphiphilicblock copolymer arm, and at other substitutable locations with adifferent polymer, such as a non-amphiphilic copolymer. The copolymercan include core units that are substituted by different amphiphilicblock copolymers, wherein any suitable proportion of various amphiphilicblock copolymers can be used.

In some examples, the core unit is a cyclodextrin, for example abeta-cyclodextrin (β-CD). In some examples, the location of the corethat can be substituted by the amphiphilic block copolymer arms can be ahydroxyl-group, wherein the substituted hydroxyl has an amphiphilicblock copolymer arm substituted in place of the hydrogen atom of thehydroxyl group. For example, an unsubstituted β-CD can have 21 hydroxylgroups that can be substituted by an amphiphilic block copolymer arm. Insome examples, not all hydroxyl groups of the β-CD are substituted by anamphiphilic block copolymer arm. In some examples, the substitutedhydroxyl groups can have different amphiphilic block copolymer arms,differing in chain length, amphiphilicity, type of homopolymer subunit,of type of chemical functionality that begins or ends the blockcopolymer arm. In other examples, all hydroxyl groups of the β-CD aresubstituted by a similar amphiphilic block copolymer arm, wherein thechain lengths are the same or similar, and wherein the type ofhomopolymer subunit is similar or identical for each block copolymerarm, and wherein the type of chemical functionality that begins or endsthe block copolymer arm is identical or similar.

The core unit can include several core subunit molecules linkedtogether. In some examples, the core subunit can be any core unit asdescribed above, wherein the core subunit can be linked to another coresubunit via a chemical linkage. The core subunit molecules can be thesame or different, and can be linked together in any suitable pattern orarrangement. Differing arrangements and types of subunits can lead todifferent properties of copolymers and nanomaterials formed therefrom.The chemical linkage can be any suitable chemical linkage, for example,an alkyl group, an alkoxy group, or a polymer that includesalkyleneoxide units. In one example, the linkage is a polyethylene oxidelinkage, also referred to as a polyethylene glycol linkage. The linkagescan be substituted at any location on the core subunits. In one example,the linkages are substituted at locations on the core subunits that aresubstitutable with amphiphilic block copolymers. Any number of linkagescan be used per core subunit, provided that at least one substitutablelocation on the full core unit (e.g. all subunits combined) can besubstituted with an amphiphilic block copolymer arm. In some examples,about 0%, 1%, 2%, 5%, 10%, 20%, 50%, 80%, 90%, or about 100% of aparticular core subunit's amphiphilic copolymer-substitutable locationscan be substituted with linkage units. In some examples, the percent oflinkage-substituted locations of one core subunit can be the same ordifferent than the percent of linkage-substituted locations on anothercore subunit.

For example, the core unit can include multiple β-CD core subunitmolecules that are linked together to form a single core unit molecule.The β-CD can be linked together to form a tubular structure. Anyproportion of the total core unit structure can be a tubular structure,while the remaining proportion of the total core unit can be anotherstructure. Any suitable number of β-CD molecules can be liked togetherto form a tubular structure. For example, about 2, 3, 4, 5, 10, 20, 50,100, 500, 1000, 5000, 10,000, 20,000, or about 50,000 or more β-CD canbe linked together to form a single molecule that can be the core unitof the copolymer, including linked together in a tubular fashion. In oneexample, one or more ethylene oxide units can form the linkages betweenthe β-CD core subunits. The linkages can be substituted athydroxyl-groups which, if not substituted with linkages, could besubstituted with amphiphilic copolymer arms. In some examples, due tothe substitution with linkages, all 21 hydroxyl groups of the β-CD coresubunits may not be available for substitution by an amphiphilic blockcopolymer.

In some examples, the amphiphilic block copolymer arm can include atleast one linking unit between the homopolymer subunits of the blockcopolymer and the core unit of the amphiphilic multi-arm copolymermolecule. The linking unit can be any suitable linking unit that allowsthe core unit to be substituted with the amphiphilic block copolymer.For example, the linking unit can include an acylalkyl group. In someexamples, the linking unit can include a 2,2-dimethylacetyl group. Insome embodiments, an acyl group on the linking unit can form anester-linkage with hydroxyl groups on the core unit. In someembodiments, substitution of the amphiphilic block copolymer arm ontothe unit core includes substitution of a 2,2-dimethylacetyl group on anoxygen atom of the unit core, wherein the substituted oxygen atom can bea hydroxyl group in the unsubstituted unit core, wherein the at leastone hydrophilic homopolymer subunit or the at least one hydrophobichomopolymer subunit of the amphiphilic block copolymer arm is asubstituent at the 2-position of the 2,2-dimethylacetyl group, whereinthe acetyl group of the 2,2-diemthylacetyl group forms a ester-linkagewith the substituted oxygen atom of the unit core. In some embodiments,substitution of the amphiphilic block copolymer arm onto a β-CD unitcore has the following structure:

wherein CD-O represents the substituted beta-cyclodextrin unit, Orepresents an oxygen atom that includes a hydroxyl group in anunsubstituted beta-cyclodextrin molecule, and ABC represents the atleast one hydrophilic homopolymer and the at least one hydrophobichomopolymer of the copolymer arm.

Each amphiphilic block copolymer in a given amphiphilic multi-armcopolymer molecule can be the same, similar, or different, for examplewith regard to chain length of individual homopolymer subunits, types ofhomopolymer subunits, functionality that begins or ends the amphiphilicblock copolymer arm, or with regard to other features. An amphiphilicblock copolymer arm can include at least one hydrophilic homopolymersubunit and at least one hydrophobic homopolymer subunit. Indescriptions of hydrophobicity and hydrophilicity, in some examples theterms are not mutually exclusive. In other examples, they are mutuallyexclusive. For example, a hydrophobic subunit can have some hydrophiliccharacter, wherein it is predominantly or at least partially hydrophobicbut also at least partially hydrophilic, such that it can be classifiedas either hydrophobic or hydrophilic. In other examples, a hydrophobicsubunit can have little enough hydrophilic character that one of skillin the art would not normally classify the subunit as hydrophilic. Insome examples, a hydrophilic subunit can have some hydrophobiccharacter, wherein it is predominantly or at least partially hydrophilicbut also at least partially hydrophobic, such that it can be classifiedas either hydrophobic or hydrophilic. In other examples, a hydrophilicsubunit can have little enough hydrophobic character that one of skillin the art would not normally classify the subunit as hydrophobic.

Amphiphilic block copolymer arms are referred to as amphiphilic and ashaving at least one hydrophobic homopolymer subunit and at least onehydrophilic homopolymer subunit to mean that at least one of thehomopolymer subunits of the arm is predominantly hydrophobic, and thatat least one of the homopolymer subunits of the arm is predominantlyhydrophilic. In some examples, the at least one hydrophobic homopolymersubunit of the amphiphilic block copolymer arm has enough hydrophiliccharacter that it could be reasonably also be classified as hydrophilic,whereas in other examples, the hydrophobic homopolymer subunit haslittle enough hydrophilic character that it would not normally becharacterized as hydrophilic; however, the at least one hydrophobichomopolymer subunit of the amphiphilic copolymer arm is predominantlyhydrophobic. In some examples, the at least one hydrophilic homopolymersubunit of the amphiphilic block copolymer arm has enough hydrophobiccharacter that it could reasonably also be classified as hydrophobic,whereas in other examples, the hydrophilic homopolymer subunit haslittle enough hydrophobic character that it would not normally becharacterized as hydrophobic; however, the at least one hydrophilichomopolymer subunit of the amphiphilic copolymer arm is predominantlyhydrophilic.

In some examples, the repeating units of each homopolymer arm on aparticular copolymer molecule can be in the same or a similar repeatingunits, and can be in the same or a similar order. In other examples, therepeating units of some homopolymers on a particular copolymer moleculecan be different, or can be in a different order. Each homopolymersubunit of each block copolymer arm can include any suitable number ofrepeating units. For example, a homopolymer subunit can include about 1,2, 3, 4, 5, 10, 20, 40, 60, 80, 100, 500, 1000, 5000, 10,000, 20,000,50,000, 100,000, 500,000, or about 1,000,000 repeating units. Eachcopolymer arm on a particular copolymer molecule can have the same orabout the same number of a particular repeating unit. Alternatively,some of the copolymer arms can have different numbers of a particularrepeating unit. The similarly or difference of the identity, number, ororder of repeating units in the arms of a particular copolymer molecule,can be adjusted to effect the desired properties from the copolymermolecule or from nanomaterials that can be formed therefrom.

In some examples, the at least one hydrophobic homopolymer subunit ofthe amphiphilic block copolymer arm can include any suitable hydrophobichomopolymer subunit. For example, the at least one hydrophobichomopolymer subunit of the amphiphilic block copolymer arm can includepoly(alkenylaryl) units such as, for example, polystyrene (PS) units,poly(alkenylheteroaryl) units such as, for example,poly(4-vinylpyridine) (P4VP) units, or poly(lactam) units such as, forexample, polycaprolactam (PCL) units.

In some examples, the at least one hydrophilic homopolymer subunit ofthe amphiphilic block copolymer arm can include any suitable hydrophilichomopolymer subunit. For example, the at least one hydrophilichomopolymer subunit of the amphiphilic block copolymer arm can includepoly(alkyl alkenoate) units such as, for example, poly(t-butyl acrylate)(PtBA) units, poly(alkenoic acid) units such as poly(acrylic acid) (PAA)units, or poly(alkylene oxide) units such as poly(ethylene oxide) (PEO)units. In some examples, the hydrophilic functional homopolymer subunitcan be any subunit that can coordinate to an inorganic precursor. Insome examples, the hydrophilic homopolymer subunit can be derivedchemically from a different homopolymer subunit. In some examples, thechemical derivation can occur after the homopolymer subunit has beeninstalled on the multi-arm amphiphilic copolymer. In some examples, thehydrophilic homopolymer subunit can be derived chemically from ahydrophilic homopolymer subunit, whereas in other examples, thehydrophililc homopolymer subunit can be derived chemically from ahydrophobic homopolymer subunit.

In various embodiments, amphiphilic block copolymer arms include anysuitable amphiphilic block copolymer. For example, the block copolymerarm can include at least two homopolymer subunits. For example, theamphiphilic block copolymer arms can include a hydrophilic homopolymersubunit nearest the core, followed by a hydrophobic homopolymer subunit.For example, the amphiphilic block copolymer arms can include poly(alkylalkenoate)-b-poly(alkenylaryl) such as, for example, PtBA-b-PA,poly(alkyl alkenoate)-b-poly(alkenylheteroaryl) such as, for example,PtBA-b-P4VP, poly(alkyl alkenoate)-b-poly(lactam) such as, for example,PtBA-b-PCL, poly(alkenoic acid)-b-poly(alkenylaryl) such as, forexample, PAA-b-PS, poly(alkenoic acid)-b-poly(alkenylheteroaryl) suchas, for example, PAA-b-P4VP, poly(alkenoic acid)-b-poly(lactam) such as,for example, PAA-b-PCL, poly(alkylene oxide)-b-poly(alkenylaryl) suchas, for example, PEO-b-PS, poly(alkyleneoxide)-b-poly(alkenylheteroaryl) such as, for example, PEO-b-P4VP, orpoly(alkylene oxide)-b-poly(lactam) such as, for example, PEO-b-PCL. Inanother example, the amphiphilic block copolymer arms can include ahydrophobic homopolymer subunit nearest the core, followed by ahydrophilic homopolymer subunit. For example,poly(alkenylaryl)-b-poly(alkyl alkenoate) such as, for example,PS-b-PtBA, poly(alkenylaryl)-b-poly(alkenoic acid) such as, for example,PS-b-PAA, poly(alkenylaryl)-b-poly(alkylene oxide) such as, for example,PS-b-PEO, poly(alkenylheteroaryl)-b-poly(alkyl alkenoate) such as, forexample, P4VP-b-PtBA, poly(alkenylheteroaryl)-b-poly(alkenoic acid) suchas, for example, P4VP-b-PAA, poly(alkenylheteroaryl)-b-poly(alkyleneoxide) such as, for example, P4VP-b-PEO, poly(lactam)-b-poly(alkylalkenoate) such as, for example, PCL-b-PtBA,poly(lactam)-b-poly(alkenoic acid) such as, for example, PCL-b-PAA, orpoly(lactam)-b-poly(alkylene oxide) such as, for example, PCL-b-PEO.

In some examples, the block copolymer arm can include at least threehomopolymer subunits. For example, the block copolymer arm can include ahydrophilic homopolymer subunit nearest the core, followed by ahydrophobic homopolymer subunit, followed by a hydrophilic homopolymersubunit. For example, the amphiphilic block copolymer arm can includepoly(alkyl alkenoate)-b-poly(alkenylaryl)-b-poly(alkyl alkenoate), suchas, for example, PtBA-b-PS-b-PtBA, poly(alkylalkenoate)-b-poly(alkenylaryl)-b-poly(alkenoic acid), such as, forexample, PtBA-b-PS-b-PAA, poly(alkylalkenoate)-b-poly(alkenylaryl)-b-poly(alkylene oxide), such as, forexample, PtBA-b-PS-b-PEO, poly(alkylalkenoate)-b-poly(alkenylheteroaryl)-b-poly(alkyl alkenoate), such as,for example, PtBA-b-P4VP-b-PtBA, poly(alkylalkenoate)-b-poly(alkenylheteroaryl)-b-poly(alkenoic acid), such as, forexample, PtBA-b-P4VP-b-PAA, poly(alkylalkenoate)-b-poly(alkenylheteroaryl)-b-poly(alkylene oxide), such as,for example, PtBA-b-P4VP-b-PEO, poly(alkylalkenoate)-b-poly(lactam)-b-poly(alkyl alkenoate), such as, for example,PtBA-b-PCL-b-PtBA, poly(alkyl alkenoate)-b-poly(lactam)-b-poly(alkenoicacid), such as, for example, PtBA-b-PCL-b-PAA, poly(alkylalkenoate)-b-poly(lactam)-b-poly(alkylene oxide), such as, for example,PtBA-b-PCL-b-PEO, poly(alkenoic acid)-b-poly(alkenylaryl)-b-poly(alkylalkenoate), such as, for example, PAA-b-PS-b-PtBA, poly(alkenoicacid)-b-poly(alkenylaryl)-b-poly(alkenoic acid), such as, for example,PAA-b-PS-b-PAA, poly(alkenoic acid)-b-poly(alkenylaryl)-b-poly(alkyleneoxide), such as, for example, PAA-b-PS-b-PEO, poly(alkenoicacid)-b-poly(alkenylheteroaryl)-b-poly(alkyl alkenoate), such as, forexample, PAA-b-P4VP-b-PtBA, poly(alkenoicacid)-b-poly(alkenylheteroaryl)-b-poly(alkenoic acid), such as, forexample, PAA-b-P4VP-b-PAA, poly(alkenoicacid)-b-poly(alkenylheteroaryl)-b-poly(alkylene oxide), such as, forexample, PAA-b-P4VP-b-PEO, poly(alkenoicacid)-b-poly(lactam)-b-poly(alkyl alkenoate), such as, for example,PAA-b-PCL-b-PtBA, poly(alkenoic acid)-b-poly(lactam)-b-poly(alkenoicacid), such as, for example, PAA-b-PCL-b-PAA, poly(alkenoicacid)-b-poly(lactam)-b-poly(alkylene oxide), such as, for example,PAA-b-PCL-b-PEO, poly(alkylene oxide)-b-poly(alkenylaryl)-b-poly(alkylalkenoate), such as, for example, PEO-b-PS-b-PtBA, poly(alkyleneoxide)-b-poly(alkenylaryl)-b-poly(alkenoic acid), such as, for example,PEO-b-PS-b-PAA, poly(alkylene oxide)-b-poly(alkenylaryl)-b-poly(alkyleneoxide), such as, for example, PEO-b-PS-b-PEO, poly(alkyleneoxide)-b-poly(alkenylheteroaryl)-b-poly(alkyl alkenoate), such as, forexample, PEO-b-P4VP-b-PAA, poly(alkyleneoxide)-b-poly(alkenylheteroaryl)-b-poly(alkenoic acid), such as, forexample, PEO-b-P4VP-b-PAA, poly(alkyleneoxide)-b-poly(alkenylheteroaryl)-b-poly(alkylene oxide), such as, forexample, PEO-b-P4VP-b-PEO, poly(alkyleneoxide)-b-poly(lactam)-b-poly(alkyl alkenoate), such as, for example,PEO-b-PCL-b-PtBA, poly(alkylene oxide)-b-poly(lactam)-b-poly(alkenoicacid), such as, for example, PEO-b-PCL-b-PtBA, or poly(alkyleneoxide)-b-poly(lactam)-b-poly(alkylene oxide), such as, for example,PEO-b-PCL-b-PEO

For example, the block copolymer arm can include at least threehomopolymer subunits, with a hydrophilic homopolymer subunit nearest thecore, followed by a hydrophilic homopolymer subunit, followed by ahydrophobic homopolymer subunit. For example, the amphiphilic blockcopolymer arm can include poly(alkyl alkenoate)-b-poly(alkenoicacid)-b-poly(alkenylaryl), such as, for example, PtBA-b-PAA-b-PS,poly(alkyl alkenoate)-b-poly(alkenoic acid)-b-poly(alkenylheteroaryl),such as, for example, PtBA-b-PAA-b-P4VP, poly(alkylalkenoate)-b-poly(alkenoic acid)-b-poly(lactam), such as, for example,PtBA-b-PAA-b-PCL, poly(alkyl alkenoate)-b-poly(alkyleneoxide)-b-poly(alkenylaryl), such as, for example, PtBA-b-PEO-b-PS,poly(alkyl alkenoate)-b-poly(alkylene oxide)-b-poly(alkenylheteroaryl),such as, for example, PtBA-b-PEO-b-P4VP, poly(alkylalkenoate)-b-poly(alkylene oxide)-b-poly(lactam), such as, for example,PtBA-b-PEO-b-PCL, poly(alkenoic acid)-b-poly(alkylalkenoate)-b-poly(alkenylaryl), such as, for example, PAA-b-PtBA-b-PS,poly(alkenoic acid)-b-poly(alkyl alkenoate)-b-poly(alkenylheteroaryl),such as, for example, PAA-b-PtBA-b-P4VP, poly(alkenoicacid)-b-poly(alkyl alkenoate)-b-poly(lactam), such as, for example,PAA-b-PtBA-b-PCL, poly(alkenoic acid)-b-poly(alkyleneoxide)-b-poly(alkenylaryl), such as, for example, PAA-b-PEO-b-PS,poly(alkenoic acid)-b-poly(alkylene oxide)-b-poly(alkenylheteroaryl),such as, for example, PAA-b-PEO-b-P4VP, poly(alkenoicacid)-b-poly(alkylene oxide)-b-poly(lactam), such as, for example,PAA-b-PEO-b-PCL, poly(alkylene oxide)-b-poly(alkenoicacid)-b-poly(alkenylaryl), such as, for example, PEO-b-PAA-b-PS,poly(alkylene oxide)-b-poly(alkenoic acid)-b-poly(alkenylheteroaryl),such as, for example, PEO-b-PAA-b-P4VP, poly(alkyleneoxide)-b-poly(alkenoic acid)-b-poly(lactam), such as, for example,PEO-b-PAA-b-PCL, poly(alkylene oxide)-b-poly(alkylalkenoate)-b-poly(alkenylaryl), such as, for example, PEO-b-PtBA-b-PS,poly(alkylene oxide)-b-poly(alkyl alkenoate)-b-poly(alkenylheteroaryl),such as, for example, PEO-b-PtBA-b-P4VP, or poly(alkyleneoxide)-b-poly(alkyl alkenoate)-b-poly(lactam), such as, for example,PEO-b-PtBA-b-PCL.

For example, the block copolymer arm can include at least threehomopolymer subunits, with a hydrophilic homopolymer subunit nearest thecore, followed by a hydrophobic homopolymer subunit, followed by ahydrophobic homopolymer subunit. For example, the amphiphilic blockcopolymer arm can include poly(alkylalkenoate)-b-poly(alkenylaryl)-b-poly(alkenylheteroaryl), such as, forexample, PtBA-b-PS-b-P4VP, poly(alkylalkenoate)-b-poly(alkenylaryl)-b-poly(lactam), such as, for example,PtBA-b-PS-b-PCL, poly(alkylalkenoate)-b-poly(alkenylheteroaryl)-b-poly(alkenylaryl), such as, forexample, PtBA-b-P4VP-b-PS, poly(alkylalkenoate)-b-poly(alkenylheteroaryl)-b-poly(lactam), such as, forexample, PtBA-b-P4VP-b-PCL, poly(alkylalkenoate)-b-poly(lactam)-b-poly(alkenylaryl), such as, for example,PtBA-b-PCL-b-PS, poly(alkylalkenoate)-b-poly(lactam)-b-poly(alkenylheteroaryl), such as, forexample, PtBA-b-PCL-b-P4VP, poly(alkenoicacid)-b-poly(alkenylaryl)-b-poly(alkenylheteroaryl), such as, forexample, PAA-b-PS-b-P4VP, poly(alkenoicacid)-b-poly(alkenylaryl)-b-poly(lactam), such as, for example,PAA-b-PS-b-PCL, poly(alkenoicacid)-b-poly(alkenylheteroaryl)-b-poly(alkenylaryl), such as, forexample, PAA-b-P4VP-b-PS, poly(alkenoicacid)-b-poly(alkenylheteroaryl)-b-poly(lactam), such as, for example,PAA-b-P4VP-b-PCL, poly(alkenoicacid)-b-poly(lactam)-b-poly(alkenylaryl), such as, for example,PAA-b-PCL-b-PS, poly(alkenoicacid)-b-poly(lactam)-b-poly(alkenylheteroaryl), such as, for example,PAA-b-PCL-b-P4VP, poly(alkyleneoxide)-b-poly(alkenylaryl)-b-poly(alkenylheteroaryl), such as, forexample, PEO-b-PS-b-P4VP, poly(alkyleneoxide)-b-poly(alkenylaryl)-b-poly(lactam), such as, for example,PEO-b-PS-b-PCL, poly(alkyleneoxide)-b-poly(alkenylheteroaryl)-b-poly(alkenylaryl), such as, forexample, PEO-b-P4VP-b-PS, poly(alkyleneoxide)-b-poly(alkenylheteroaryl)-b-poly(lactam), such as, for example,PEO-b-P4VP-b-PCL, poly(alkyleneoxide)-b-poly(lactam)-b-poly(alkenylheteroaryl), such as, for example,PEO-b-PCL-b-P4VP, or poly(alkyleneoxide)-b-poly(lactam)-b-poly(alkenylaryl), such as, for example,PEO-b-PCL-b-PS.

For example, the block copolymer arm can include at least threehomopolymer subunits, with a hydrophobic homopolymer subunit nearest thecore, followed by a hydrophobic homopolymer subunit, followed by ahydrophilic homopolymer subunit. For example, the amphiphilic blockcopolymer arm can includepoly(alkenylaryl)-b-poly(alkenylheteroaryl)-b-poly(alkyl alkenoate),such as, for example, PS-b-P4VP-b-PtBA,poly(alkenylaryl)-b-poly(alkenylheteroaryl)-b-poly(alkenoic acid), suchas, for example, PS-b-P4VP-b-PAA,poly(alkenylaryl)-b-poly(alkenylheteroaryl)-b-poly(alkylene oxide), suchas, for example, PS-b-P4VP-b-PEO,poly(alkenylaryl)-b-poly(lactam)-b-poly(alkyl alkenoate), such as, forexample, PS-b-PCL-b-PtBA,poly(alkenylaryl)-b-poly(lactam)-b-poly(alkenoic acid), such as, forexample, PS-b-PCL-b-PAA,poly(alkenylaryl)-b-poly(lactam)-b-poly(alkylene oxide), such as, forexample, PS-b-PCL-b-PEO,poly(alkenylheteroaryl)-b-poly(alkenylaryl)-b-poly(alkyl alkenoate),such as, for example, P4VP-b-PS-b-PtBA,poly(alkenylheteroaryl)-b-poly(alkenylaryl)-b-poly(alkenoic acid), suchas, for example, P4VP-b-PS-b-PAA,poly(alkenylheteroaryl)-b-poly(alkenylaryl)-b-poly(alkylene oxide), suchas, for example, P4VP-b-PS-b-PEO,poly(alkenylheteroaryl)-b-poly(lactam)-b-poly(alkyl alkenoate), such as,for example, P4VP-b-PCL-b-PtBA,poly(alkenylheteroaryl)-b-poly(lactam)-b-poly(alkenoic acid), such as,for example, P4VP-b-PCL-b-PAA,poly(alkenylheteroaryl)-b-poly(lactam)-b-poly(alkylene oxide), such as,for example, P4VP-b-PCL-b-PEO,poly(lactam)-b-poly(alkenylaryl)-b-poly(alkyl alkenoate), such as, forexample, PCL-b-PS-b-PtBA,poly(lactam)-b-poly(alkenylaryl)-b-poly(alkenoic acid), such as, forexample, PCL-b-PS-b-PtBA,poly(lactam)-b-poly(alkenylaryl)-b-poly(alkylene oxide), such as, forexample, PCL-b-PS-b-PEO,poly(lactam)-b-poly(alkenylheteroaryl)-b-poly(alkyl alkenoate), such as,for example, PCL-b-P4VP-b-PtBA,poly(lactam)-b-poly(alkenylheteroaryl)-b-poly(alkenoic acid), such as,for example, PCL-b-P4VP-b-PAA, orpoly(lactam)-b-poly(alkenylheteroaryl)-b-poly(alkylene oxide), such as,for example, PCL-b-P4VP-b-PEO.

For example, the block copolymer arm can include at least threehomopolymer subunits, with a hydrophobic homopolymer subunit nearest thecore, followed by a hydrophilic homopolymer subunit, followed by ahydrophobic homopolymer subunit. For example, the amphiphilic blockcopolymer arm can include poly(alkenylaryl)-b-poly(alkenoicacid)-b-poly(alkenylaryl), such as, for example, PS-b-PAA-b-PS,poly(alkenylaryl)-b-poly(alkenoic acid)-b-poly(alkenylheteroaryl), suchas, for example, PS-b-PAA-b-P4VP, poly(alkenylaryl)-b-poly(alkenoicacid)-b-poly(lactam), such as, for example, PS-b-PAA-b-PCL,poly(alkenylaryl)-b-poly(alkyl alkenoate)-b-poly(alkenylaryl), such as,for example, PS-b-PtBA-b-PS, poly(alkenylaryl)-b-poly(alkylalkenoate)-b-poly(alkenylheteroaryl), such as, for example,PS-b-PtBA-b-P4VP, poly(alkenylaryl)-b-poly(alkylalkenoate)-b-poly(lactam), such as, for example, PS-b-PtBA-b-PCL,poly(alkenylaryl)-b-poly(alkylene oxide)-b-poly(alkenylaryl), such as,for example, PS-b-PEO-b-PS, poly(alkenylaryl)-b-poly(alkyleneoxide)-b-poly(alkenylheteroaryl), such as, for example, PS-b-PEO-b-P4VP,poly(alkenylaryl)-b-poly(alkylene oxide)-b-poly(lactam), such as, forexample, PS-b-PEO-b-PCL, poly(alkenylheteroaryl)-b-poly(alkenoicacid)-b-poly(alkenylaryl), such as, for example, P4VP-b-PAA-b-PS,poly(alkenylheteroaryl)-b-poly(alkenoic acid)-b-poly(alkenylheteroaryl),such as, for example, P4VP-b-PAA-b-P4VP,poly(alkenylheteroaryl)-b-poly(alkenoic acid)-b-poly(lactam), such as,for example, P4VP-b-PAA-b-PCL, poly(alkenylheteroaryl)-b-poly(alkylalkenoate)-b-poly(alkenylaryl), such as, for example, P4VP-b-PtBA-b-PS,poly(alkenylheteroaryl)-b-poly(alkylalkenoate)-b-poly(alkenylheteroaryl), such as, for example,P4VP-b-PtBA-b-P4VP, poly(alkenylheteroaryl)-b-poly(alkylalkenoate)-b-poly(lactam), such as, for example, P4VP-b-PtBA-b-PCL,poly(alkenylheteroaryl)-b-poly(alkylene oxide)-b-poly(alkenylaryl), suchas, for example, P4VP-b-PEO-b-PS,poly(alkenylheteroaryl)-b-poly(alkyleneoxide)-b-poly(alkenylheteroaryl), such as, for example,P4VP-b-PEO-b-P4VP, poly(alkenylheteroaryl)-b-poly(alkyleneoxide)-b-poly(lactam), such as, for example, P4VP-b-PEO-b-PCL,poly(lactam)-b-poly(alkenoic acid)-b-poly(alkenylaryl), such as, forexample, PCL-b-PAA-b-PS, poly(lactam)-b-poly(alkenoicacid)-b-poly(alkenylheteroaryl), such as, for example, PCL-b-PAA-b-P4VP,poly(lactam)-b-poly(alkenoic acid)-b-poly(lactam), such as, for example,PCL-b-PAA-b-PCL, poly(lactam)-b-poly(alkylalkenoate)-b-poly(alkenylaryl), such as, for example, PCL-b-PtBA-b-PS,poly(lactam)-b-poly(alkyl alkenoate)-b-poly(alkenylheteroaryl), such as,for example, PCL-b-PtBA-b-P4VP, poly(lactam)-b-poly(alkylalkenoate)-b-poly(lactam), such as, for example, PCL-b-PtBA-b-PCL,poly(lactam)-b-poly(alkylene oxide)-b-poly(alkenylaryl), such as, forexample, PCL-b-PEO-b-PS, poly(lactam)-b-poly(alkyleneoxide)-b-poly(alkenylheteroaryl), such as, for example,PCL-b-PEO-b-P4VP, or poly(lactam)-b-poly(alkylene oxide)-b-poly(lactam),such as, for example, PCL-b-PEO-b-PCL.

For example, the block copolymer arm can include at least threehomopolymer subunits, with a hydrophobic homopolymer subunit nearest thecore, followed by a hydrophilic homopolymer subunit, followed by ahydrophilic homopolymer subunit. For example, the amphiphilic blockcopolymer arm can include poly(alkenylaryl)-b-poly(alkenoicacid)-b-poly(alkyl alkenoate), such as, for example, PS-b-PAA-b-PtBA,poly(alkenylaryl)-b-poly(alkenoic acid)-b-poly(alkylene oxide), such as,for example, PS-b-PAA-b-PEO, poly(alkenylaryl)-b-poly(alkylalkenoate)-b-poly(alkenoic acid), such as, for example, PS-b-PtBA-b-PAA,poly(alkenylaryl)-b-poly(alkyl alkenoate)-b-poly(alkylene oxide), suchas, for example, PS-b-PtBA-b-PEO, poly(alkenylaryl)-b-poly(alkyleneoxide)-b-poly(alkyl alkenoate), such as, for example, PS-b-PEO-b-PtBA,poly(alkenylaryl)-b-poly(alkylene oxide)-b-poly(alkenoic acid), such as,for example, PS-b-PEO-b-PAA, poly(alkenylheteroaryl)-b-poly(alkenoicacid)-b-poly(alkyl alkenoate), such as, for example, P4VP-b-PAA-b-PtBA,poly(alkenylheteroaryl)-b-poly(alkenoic acid)-b-poly(alkylene oxide),such as, for example, P4VP-b-PAA-b-PEO,poly(alkenylheteroaryl)-b-poly(alkyl alkenoate)-b-poly(alkenoic acid),such as, for example, P4VP-b-PtBA-b-PAA,poly(alkenylheteroaryl)-b-poly(alkyl alkenoate)-b-poly(alkylene oxide),such as, for example, P4VP-b-PtBA-b-PEO,poly(alkenylheteroaryl)-b-poly(alkylene oxide)-b-poly(alkyl alkenoate),such as, for example, P4VP-b-PEO-b-PtBA,poly(alkenylheteroaryl)-b-poly(alkylene oxide)-b-poly(alkenoic acid),such as, for example, P4VP-b-PEO-b-PAA, poly(lactam)-b-poly(alkenoicacid)-b-poly(alkyl alkenoate), such as, for example, PCL-b-PAA-b-PtBA,poly(lactam)-b-poly(alkenoic acid)-b-poly(alkylene oxide), such as, forexample, PCL-b-PAA-b-PEO, poly(lactam)-b-poly(alkylalkenoate)-b-poly(alkenoic acid), such as, for example,PCL-b-PtBA-b-PAA, poly(lactam)-b-poly(alkyl alkenoate)-b-poly(alkyleneoxide), such as, for example, PCL-b-PtBA-b-PEO,poly(lactam)-b-poly(alkylene oxide)-b-poly(alkyl alkenoate), such as,for example, PCL-b-PEO-b-PtBA, or poly(lactam)-b-poly(alkyleneoxide)-b-poly(alkenoic acid), such as, for example, PCL-b-PEO-b-PAA.

In some examples, the block copolymer arms of the copolymer molecule caninclude linear block copolymers. In some examples, the block copolymerarms of the copolymer molecule can include graft copolymers (e.g.polymer side chains). The graft copolymer can include side chains thatinclude any repeating unit disclosed herein. For example, the graftcopolymer side chains can include hydrophobic subunits such aspoly(alkenylaryl) units such as, for example, polystyrene (PS) units,poly(alkenylheteroaryl) units such as, for example,poly(4-vinylpyridine) (P4VP) units, or poly(lactam) units such as, forexample, polycaprolactam (PCL) units; or hydrophilic units such aspoly(alkyl alkenoate) units such as, for example, poly(t-butyl acrylate)(PtBA) units, poly(alkenoic acid) units such as poly(acrylic acid) (PAA)units, or poly(alkylene oxide) units such as poly(ethylene oxide) (PEO)units.

In some examples, the block copolymer arms can include any suitablechemical functionality as the end-group of the block copolymer arms,e.g. as the chemical group opposite the core molecule on the blockcopolymer arm. In some examples, the end-group of the block copolymerarms can be the same, similar, or different. In some examples, theend-group of the block copolymer arms can be an azide group (e.g. —N₃).The end-group can allow for any suitable further chemical reactions,which can occur before, during, or after addition of an inorganicprecursor to form a nanomaterial; in some embodiments no precursor isadded and the copolymer molecule is desired. In some examples, the endgroup allows click chemistry to occur. For example, an azide group canallow a Huisgen 1,3-dipolar cycloaddition between an azide and aterminal or internal alkyne to give a 1,2,3-triazole. Any suitableend-group can be used, to allow for any suitable reaction to take placelater, or allow for any desired functionality on the surface of orinside of a resulting nanomaterial.

In some examples, the homopolymer sections of the block copolymer armscan be connected directly to one another. In other examples, thehomopolymer sections of the block copolymer arms can be connected to oneanother via any suitable linking unit. One example of a suitable linkingunit between homopolymer sections of the block copolymer arms is a1,2,3-triazole ring that connects one polymer subunit end-unit of onehomopolymer section to one polymer subunit end-unit of anotherhomopolymer section, via the 1- and 4-positions of the heterocycle. Asdescribed above and below, such a heterocyclic linking unit can beformed using a Huisgen 1,3-dipolar cycloaddition between an azide and aterminal or internal alkyne, an example of click chemistry.

Method of Making an Amphiphilic Multi-Arm Copolymer

Various embodiments of the present invention provide a method for makingan amphiphilic multi-arm copolymer. The method can generate anyamphiphilic multi-arm copolymer described herein. The method can be anysuitable method that generates any amphiphilic multi-arm copolymerdescribed herein. The method can include contacting a core with a seriesof polymer subunits, to form a core that is substituted with blockcopolymer arms, wherein the block copolymer arms are amphiphilic. Thecore can be any suitable core, and the block copolymer arms can be anysuitable block copolymer arms that are amphiphilic. A variety ofpolymeric shapes can be synthesized using the method, includingstar-like, and bottlebrush. The method can be used to make Januspolymers. The method can allow production of polymers with well-designedmolecular structures, different functional blocks, highly controllablemolecular weight, uniform size, and varied ratio of functional blocks.Any suitable polymerization method can be used, and it is to beunderstood that the method of the present invention is not limited toany of the specific examples of polymerization given herein. The methodgenerally includes living polymerization, for example, atom transferradical polymerization (ATRP), reversible addition-fragmentationchain-transfer (RAFT) polymerization, anionic polymerization, orcoordination-insertion ring-opening polymerization).

The method can also include the use of click chemistry. An example ofclick chemistry can include a cyclization reaction between an azidegroup on the end of one polymer subunit and alkyne group on the end ofanother polymer subunit to give a 1,2,3-triazole ring that connects onepolymer subunit to the other via the 1- and 4-positions of theheterocycle. An example is illustrated in FIG. 1. FIG. 1 illustrates thesynthesis of a star-like PAA-b-PEO amphiphilic multi-arm copolymer via acombination of ATRP and click chemistry. First, a 21-arm star-like PtBApolymer with azide end-groups (PtBA-N₃) can be prepared via the reactionof a star-like PtBA polymer with a bromine end-group (PtBA-Br) withsodium azide. A propargyl group can be introduced to a polyethyleneoxide(PEO) chain-end by a nucleophilic substitution reaction between theactive hydroxyl end group of the PEO and propargyl bromide, giving analkyne-terminated PEO. Finally, a reaction between an azide end-group ofPtBA and the alkenyl end-group of the PEO gives click chemistry to linkthe azide and alkenyl groups together via 1,2,3-triazole units, giving aPtBA-b-PEO 21-arm star-like block copolymer. The final product, astar-like PAA-b-PEO, can be obtained via the hydrolysis of PtBA block inTFA.

In some examples, the method includes providing a core that includeshydroxyl functional groups. The method can include contacting the corewith a halogenated esterification reagent. The contacting gives amacro-initiator core that includes the core with at least some of thehydroxyl functional groups esterified by the halogenated esterificationreagent. The method can include contacting the macro-initiator core witha first homopolymer subunit precursor. The contacting of themacro-initiator core can give a first substituted core. The firstsubstituted core includes the macro-initiator core wherein at least onehalogen atom on the core (e.g. the halogen atom that came from thehalogenated esterification reagent) is replaced with a first homopolymerincludes subunits that include a reaction product of the firsthomopolymer subunit precursor. The method can include contacting thefirst substituted core with a second homopolymer subunit precursor. Thesecond homopolymer subunit precursor is different from the firsthomopolymer subunit precursor. The contacting gives a second substitutedcore that includes the first substituted core, wherein the firsthomopolymer is substituted with a second homopolymer that includessubunits that include a reaction product of the second homopolymerprecursor. The first and second homopolymer together include anamphiphilic block copolymer arm.

The core unit can be any appropriate core unit. The core unit can be asingle molecule. The core unit can be a large molecule that includesseveral smaller molecules linked together. The core unit can include anysuitable number of locations that can be substituted by the amphiphilicblock copolymer arms. In some examples, the core unit includes about 1,2, 3, 4, 5, 10, 20, 30, 40, or about 50 or more locations that can besubstituted with arms. In some examples, the core unit is acyclodextrin, for example a beta-cyclodextrin (β-CD). For example, anunsubstituted β-CD can have 21 hydroxyl groups that can be substitutedby an amphiphilic block copolymer arm. In some examples, not allhydroxyl groups of the β-CD are substituted by an amphiphilic blockcopolymer arm. In some examples, the substituted hydroxyl groups canhave different amphiphilic block copolymer arms, differing in chainlength, amphiphilicity, type of homopolymer subunit, of type of chemicalfunctionality that begins or ends the block copolymer arm. In otherexamples, all hydroxyl groups of the β-CD are substituted by a similaramphiphilic block copolymer arm, wherein the chain lengths are the sameor similar, and wherein the type of homopolymer subunit is similar oridentical for each block copolymer arm, and wherein the type of chemicalfunctionality that begins or ends the block copolymer arm is identicalor similar.

The halogenated esterification reagent can be any suitable reagent thathas a halogen substituent and that can form an ester with a hydroxylgroup. For example, a halogenated carboxylic acid can be a halogenatedesterification reagent. The halogenated carboxylic acid can be anycarboxylic acid, including an alkanoic, alkenoic, or alkynoic acid, withany degree or branching, that includes a halogen substituent. In someexamples, the halogenated esterification reagent can be2-bromoisobutyryl bromide.

In some embodiments, the method can further include contacting thesecond substituted core with a third homopolymer subunit precursor. Thethird homopolymer subunit precursor is different from the secondhomopolymer subunit precursor. The contacting gives a third substitutedcore that includes the second substituted core wherein the secondhomopolymer is substituted with a third homopolymer that includessubunits that include a reaction product of the third homopolymersubunit precursor.

The first homopolymer subunit precursor, the second homopolymer subunitprecursor, and the third homopolymer subunit precursor, or any otherhomopolymer subunit precursor, can be any suitable homopolymerprecursor. For example, the homopolymer precursor can be an alkylalkenoate, an alkenoic acid, an alkylene glycol, an alkenylarylcompound, an alkenylheteroaryl compound, or a lactam. A reaction productof an alkyl alkenoate subunit precursor can include, for example, alkylalkylenoate subunits. A reaction product of an alkenoic acid subunitprecursor can include, for example, alkylenoic acid subunits. A reactionproduct of an alkylene glycol subunit precursor can include, forexample, alkylene oxide subunits. A reaction product of an alkenylarylsubunit precursor can include, for example, alkylenylaryl subunits. Areaction product of an alkenylheteroaryl subunit precursor can include,for example, alkylenylheteroaryl subunits. A reaction product of alactam can include, for example, amide subunits. For example, thehomopolymer precursor can be t-butyl acrylate, acrylic acid, ethyleneglycol, styrene, 4-vinylpyridine, or caprolactam. A reaction product oft-butyl acrylate can include, for example, t-butyl propylenoatesubunits. A reaction product of acrylic acid can include, for example,propylenoic acid subunits. A reaction product of ethylene glycol caninclude, for example, ethylene oxide subunits. A reaction product ofstyrene can include, for example, phenylethylene units. A reactionproduct of 4-vinylpyridine can include, for example, 4-ethylenylpyridinesubunits. A reaction product of caprolactam can include, for example,hexanamidylene subunits.

The method can include the use of a suitable solvent during any step.For example, the method can include the use of organic solvents such as1-methyl-2-pyrrolidione (NMP), methyl ethyl ketone, methylene chloride,tetrahydrofuran (THF), dimethylformamide (DMF).

The method can include the use of variation of temperature. For example,during additions of reagents, the temperature can be kept low to helpkeep an exothermic reaction under control. In another example, thetemperature can be kept low during reactions to control the rate of thereaction, which during polymerization can influence the rate of thereaction. For example, during the polymerization steps, the reactionflask holding the mixture can be immersed in cold liquids, such asliquid nitrogen, in order to slow down or stop the reaction, as desired.In another example, an elevated temperature is used to effect a desiredreaction rate or to offset and endothermic chemical reaction.

Various initiators or catalysts can be added to initiate or catalystpolymerization steps. For example, catalyst systems, including forexample radical initiator mixtures, can be added during polymerization.For example, cuprous bromide (CuBr) can be used, andN,N,N′,N″,N″-pentamethyldiethylene triamine (PMDETA) can be used. Anysuitable polymerization initiator or catalyst can be used duringpolymerization steps.

Various purification steps can occur during the method. For example,standard workup procedures to remove aqueously soluble or insolubleimpurities can be used, such as washing with basic aqueous solutions,eluting through silica or alumina columns (for filtration orchromatography) using an appropriate solvent, or filtration through anysuitable media using an appropriate solvent.

Drying steps can be included in the method. The drying steps can includeremoval of water. The drying steps can include the removal of anysolvent. The drying can occur under a vacuum, or at ambient pressure. Insome examples, drying can occur at low temperature.

In some embodiments, UV-cross linking can be performed on the copolymer.UV cross-linking can be effective to cross link homopolymer subunitsincluding PS, PCL, or PEO subunits. Such cross linking can causedesirable properties to occur in the copolymer, for example enhanceddurability or strength, or altered polarity of functional groups.

Nanomaterials

Various embodiments of the present invention provide nanomaterials. Thenanomaterial can be any nanomaterial derived from an amphiphilicmulti-arm copolymer described herein. The nanomaterial is formed bycontacting an inorganic precursor with the amphiphilic multi-armcopolymer. The contacting causes the inorganic precursor to coordinatewith homopolymer subunits of the block copolymer arms that havefunctional groups for coordination, forming the nanomaterial.

By using the appropriate copolymer, for example by using a particularcore, or by using a particular pattern or arrangement of block copolymersubunits, or by adjusting the size of the copolymer by using variouschain-lengths of the blocks of the copolymer, a wide variety ofnanomaterials can be formed. For example, by using a copolymer withcoordinatable-homopolymer subunits nearest the core, the nanomaterialcan have a core-inorganic portion, with functional organic groupsextending from the core-inorganic portion of the nanomaterial. Byadjusting the identity of the functional groups extending from thesurface, various properties of the nanomaterial can be varied. Forexample, by using hydrophobic functional groups, the nanomaterial can bemade to be organic-solvent soluble. For example, by using hydrophilicfunctional groups, the nanomaterial can be made to be water soluble. Insome embodiments, by using a copolymer with coordinatable-homopolymersubunits separated from the core by one or morenon-coordinatable-homopolymer subunits, a nanomaterial can be made thathas an inorganic-shell that surrounds an organic core. By using acopolymer that as coordinatable-homopolymer subunits nearest the core,followed by non-coordinatable-homopolymer subunits, followed bycoordinatable-subunits, a nanomaterial can be formed that has both aninorganic-core and an inorganic-shell.

The coordination between the coordinatable homopolymer subunits and thecoordinating inorganic precursor can be any suitable coordination. Insome embodiments, the coordination can include inter-atomic forces thatare equivalent to a chemical bond, such as a covalent bond, or an ionicbond. In some embodiments, the coordination can include inter-atomicforces that are not as strong as a covalent bond, but that are strongenough to hold the inorganic precursor compound together with theamphiphilic multi-arm copolymer. In some embodiments, aftercoordination, the complex can be further treated to cause the inorganicmaterial to fuse together or to undergo a chemical change that causesadditional forces other than just the coordination force to hold theinorganic compound together with the copolymer molecule. For example,the nanomaterial can be treated with heat. In another example, thenanomaterial can be chemically treated. Some types ofcoordinatable-homopolymer subunits can be coordinated more strongly withparticular kinds of inorganic precursors than others; anypost-coordination treatment that occurs can be dependent on the strengthof this interaction. In some examples, the nanomaterial undergoes nofurther treatment, and the coordination of the inorganic precursor withthe copolymer molecule is strong enough to allow for the intended use ofthe nanomaterial. In some examples, the inorganic precursor coordinatesto poly(acrylic acid) subunits of the amphiphilic multi-arm copolymermolecule. In some examples, the coordination complex between the one ormore inorganic precursors and the copolymer molecule can be consideredto be a single molecule.

Method of Making a Nanomaterial

Various embodiments of the present invention provide a method of makinga nano material. The nanomaterial can be any suitable nanomaterialdescribed herein. The method of making a nanomaterial can be anysuitable method that gives a nanoparticle described herein. The methodof making a nanomaterial can include the method of making an amphiphilicmulti-armed copolymer described herein, followed by a step of contactingan inorganic precursor molecule with the precursor. In another example,the method of making a nanomaterial includes adding an inorganicprecursor molecule to an amphiphilic multi-armed copolymer, wherein theamphiphilic multi-armed copolymer is made or obtained by any suitablemethod.

The inorganic precursor can be an ion. The inorganic compound can be aneutral species. The inorganic compound can be a metal. The inorganiccompound can be a transition metal. The inorganic compound can be anycompound that can coordinate to a homopolymer in the amphiphilicmulti-armed copolymer.

The inorganic precursor can be formed from an inorganic precursorsource. The inorganic precursor source can be any suitable compound orcompounds that can generate an inorganic precursor. For precursorsources that include multiple compounds, the compound can be combinedprior to contacting with the copolymer molecule, while contacting thecopolymer molecule, or after contacting the copolymer molecule. Theprecursor source can be combined prior to contacting. The inorganicprecursor source can be any compound or compounds wherein a part of theprecursor source or a compound or species derived from the precursorsource is the inorganic precursor. The precursor source can be acompound that chemically affects another compound such that theinorganic precursor is produced. The inorganic precursor source can be asalt. In one example, the salt includes more than one counterion, andless than all the counterions within the salt coordinate to thehomopolymer subunit. For example, the inorganic precursor source can bea salt including an Au ion with a counterion, while the resultingcoordinating precursor compound can include only the Au ion of the salt.The inorganic precursor source can be any source of a coordinatingcompound.

In some examples, the inorganic precursor can be any suitable ion, orany suitable molecule, wherein the ion or molecule can coordinate tohomopolymer subunits of the amphiphilic multi-arm copolymer. Forexample, the inorganic precursor can be Au, Ag, Pb, Ba, Na, Tm, Fe, Cd,Ti, Zn, Cu, Sn, or any suitable ion thereof. In some examples, theinorganic precursor can be provided by a compound that includes theinorganic precursor or that undergoes a chemical reaction to provide theinorganic precursor, such as a salt of the inorganic precursor, or suchas a reaction mixture; such a compound or compounds that can provide theinorganic precursor can be called the inorganic precursor-source. Insome examples, the inorganic precursor can be Au or ions thereof, Ag orions thereof, BaTiO₃, PbTiO₃, BaSe₃, NaYF₄:Tm, Fe₃O₄ and γ-Fe₂O₃, CdSe,TiO₂, ZnO, Cu₂O, SnO, SnO₂, or any suitable ion thereof, and the like,including any suitable mixture thereof. In some examples, the materialused enables the formation of nanoparticles useful in particular areasof technology, such as, for example, noble metallic nanomaterials whichcan be used, for example, for surface plasmonic applications (e.g.,inorganic precursors such as Au or Ag or any suitable ion thereof, forexample provided by inorganic precursor-sources such as any suitablesalt of Au or Ag, such as for example AgNO₃ or HAuCl₄), ferroelectricnanomaterials which can be used, for example, in capacitors, transducersand actuators (e.g., inorganic precursors such as PbTiO₃ or BaTiO₃,provided by inorganic precursor sources such as for examplePbTi[OCH(CH₃)₂]₆ or (BaCl₂.2H₂O+TiO₄+NaOH), respectively),thermoelectric nanomaterials which can be used, for example, forconverting the waste heat into electricity (e.g., inorganic precursorssuch as Bi₂Te₃ and Bi₂Se₃, provided by inorganic precursor-sources suchas for example BiCl₃+Te or BiCl₃+Se, respectively), upconversionnanomaterials which can be used, for example, for energy and biomedicalapplications by converting low energy IR photons into UV and visiblephotons (e.g., rare-earth fluorescent; e.g., inorganic precursors suchas NaYF₄:Tm or ions thereof, provided by inorganic precursor-sourcessuch as for example NaF:YCl₃+TmCl₃), superparamagnetic ion oxidenanomaterials which can be used, for example, for magnetic device andbiomedical applications (“SPION”; e.g., inorganic precursors such asFe₃O₄ and γ-Fe₂O₃, provided by inorganic precursor-sources such as forexample FeCl₂.4H₂O+FeCl₃.6H₂O+NH₄OH), n-type or p-type semiconductornanomaterials which can be used, for example, for solar cells, waterpurification, and bioimaging and biosensors applications (e.g.,inorganic precursors such as CdSe, TiO₂ and ZnO, or Cu₂O and SnO₂,provided by inorganic precursor-sources such as Cd(acac)₂+Se, TTIP(Ti(OC₃H₇)₄), (Zn(NO₃).6H₂O+KOH; or copper (I) acetate (CuOAc) andSnCl₄.5H₂O+hydrochloric acid), respectively, and the like).

In some examples, the inorganic precursor-source can be any suitableinorganic precursor-source. The precursor source can include AgNO₃ andHAuCl₄ to give precursors that include Ag, Au, or ions thereof. Theprecursor source can include PbTi[OCH(CH₃)₂]₆, to give precursors thatinclude PbTiO₃. The precursor source can include BaCl₂.2H₂O+TiCl₄+NaOH,to give precursors that include BaTiO₃. The precursor source can includeBiCl₃+Te to give precursors that include Bi₂Te₃, with NaBH₄ as thereductant and NaOH as the pH-value controller. The precursor source caninclude BiCl₃+Se to give precursors that include Bi₂Se₃, with NaBH₄ asthe reductant and NaOH as the pH-value controller. The precursor sourcecan include NaF:YCl₃ (e.g. 4:1, molar ratio) as the host material andTmCl₃ as the activator to form a precursor that includes NaYF₄:Tm; othervarients include YF₃ as the host, and YbCl₃ and HoCl₃ as dopants (Yb³⁺serves as sensitizer and Ho³⁺ is the activator). The precursor sourcecan include FeCl₂.4H₂O+FeCl₃.6H₂O+ammonium hydroxide to give a precursorthat includes Fe₃O₄. The precursor source can include ferric(III)acetylacetonate (Fe(acac)₃) to give a precursor that includes γ-Fe₂O₃.The precursor source can include reaction systems includingCd(acac)₂+Se, TTIP (Ti(OC₃H₇)₄) and (Zn(NO₃).6H₂O+KOH; or copper (I)acetate (CuOAc) and SnCl₄.5H₂O+hydrochloric acid to give precursors thatinclude CdSe, TiO₂, ZnO, Cu₂O, or SnO, respectively.

In some embodiments, UV-cross linking can be performed before, during,or after contacting the precursor with the copolymer. UV cross-linkingcan be effective to cross link homopolymer subunits including PS, PCL,or PEO subunits. Such cross-linking can cause desirable properties tooccur in the nanomaterials, for example enhanced durability or strength,or altered polarity of surface functional groups.

EXAMPLES

The present invention can be better understood by reference to thefollowing examples which are offered by way of illustration. The presentinvention is not limited to the examples given herein.

Example 1 Method of Preparing an Amphiphilic Multi-Arm CopolymerIncluding a β-CD Core with Arms Including PAA-b-PS Block Copolymers

Beta-cyclodextrin (β-CD) (6.82 g) with 21 hydroxyl groups was dissolvedin anhydrous 1-methyl-2-pyrrolidone (NMP, 60 mL) at about 0° C.2-Bromoisobutyryl bromide (58.0 mL, 252 mmol) was then added dropwise tothe β-CD solution while stirring. The reaction temperature wasmaintained at about 0° C. for about 2 h and then allowed to rise slowlyto ambient temperature, after which the reaction was allowed to continuefor about 22 h. The pure atom transfer radical polymerization (ATRP)macro-initiator 21Br-β-CD (18.21 g, yield=71.2%) was thus obtained afterthe crude product was purified by washing sequentially with saturatedNaHCO₃ aqueous solution (200 mL) and DI water (200 mL). The chemicalcompositions of 21Br-β-CD were confirmed by FTIR: 2931 cm¹ (ν_(C—H)),1737 cm¹ (ν_(C═O)), 1158 cm⁻¹ (ν_(C—O—C)), and 1039 and 1105 cm⁻¹(coupled ν_(C—C) and ν_(C—O)).

Polymerization using t-butylacrylate (tBA) was then carried out using21Br-β-CD as macroinitiator with 21 ATRP initiation sites: an ampoulecharged with the CuBr (0.0707 g), N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA, 0.1707 g), 21Br-β-CD (0.1 g), tBA (42.9 mL), andmethyl ethyl ketone (43 mL) was vacuumed by three freeze-thaw-cycles atthe liquid N₂ temperature (−196° C.), then sealed and placed in an oilbath at about 60° C. The ampoules were taken out from the oil bath anddipped in liquid N₂ at 3 h to stop the polymerization. The solution wasdiluted with acetone and passed through a neutral alumina column(diameter: 10 cm, height: 20 cm) to remove the catalyst (i.e., coppersalt) and then precipitated using methanol/water (50 mL/50 mL). Afterthat, the product, 21-arm star-like β-CD-PtBA, was purified bydissolution/precipitation with acetone and methanol/water, giving 3 g of21-arm star-like β-CD-PtBA at 76.1% yield.

A star-like β-CD-PtBA-b-PS diblock copolymer was then synthesized byATRP using styrene and using the purified star-like β-CD-PtBA as a21-site macroinitiator. The ATRP of styrene was carried out in anisol atabout 90° C. using the PMDETA/CuBr catalyst system. The polymerizationwas performed in an ampoule. The reaction mixture (styrene (2.1 g):β-CD-PtBA (0.2 g): copper bromide (0.0072 g): PMDETA (0.01733g)=800:1:1:2 molar ratio) in anisole (2.1 mL, with 1 g styrene per 1 mLsolvent) was degassed with three freeze-pump-thaw cycles at the liquidN₂ temperature (−196° C.) and then placed in an about 90° C. oil bathwhich began the polymerization. After a specific polymerization time (2h), the reaction mixtures were placed in liquid N₂ to stop thepolymerization, and the content was diluted with THF (20 mL) and passedthrough a neutral alumina column (diameter: 10 cm, height: 20 cm) toremove the copper salts. The polymers were precipitated with an excessamount of methanol (50 mL), filtered, and dried under vacuum to yield21-arm, star-like diblock copolymer β-CD-PtBA-b-PS (0.28 g,yield=93.3%).

21-Arm amphiphilic star-like β-CD-PAA-b-PS was obtained by hydrolysis ofthe tert-butyl ester groups of PtBA block in the PtBA-b-PS. Star-likediblock copolymer PtBA-b-PS (0.3 g) was dissolved in CH₂Cl₂ (30 mL), andtrifluoroacetic acid (TFA, 10 mL) was added. The reaction mixture wasstirred at room temperature for about 24 h. The crude product was thenseparated by filtration and washed with CH₂Cl₂ (100 mL).

Example 2 Method of Preparing Nanoparticles

Star-like β-CD-PAA-b-PS served as a template for synthesis ofnanoparticles. The β-CD-PAA-b-PS (10 mg) was dissolved in a mixture ofdimethylformamide (DMF, 9 mL) and benzyl alcohol (1 mL) at about roomtemperature, followed by the addition of appropriate the inorganicprecursor-source or inorganic precursor (5 times molar amount ofstar-like β-CD-PAA-b-PS). The inorganic precursor was selectivelyincorporated into the inner hydrophilic PAA homopolymer through thecoordination interaction between PAA and the precursor, but not into theouter PS homopolymer, since PS has no active functional groups tocoordinate with precursor. The solution was refluxed, and thenanoparticles capped by hydrophobic PS were thus obtained. Thenanoparticles capped with PS rendered them the soluble in variousorganic solvents (e.g, toluene, chloroform, THF, and so on).

Example 3 Noble Metallic Nanoparticles

Following the general method given in Examples 1 and 2, AgNO₃ (58.9 mg)or HAuCl₄ (0.1179 g) were used as the inorganic precursor-sources, andethanol was used as the solvent. The reactions were controlled such thatdifferent temperatures were used for specific metals. About 100° C. wasused as a reaction temperature for Ag ion inorganic precursor, with areaction time of about 10 h. About 60° C. was used for Au ion inorganicprecursor, with a reaction time of about 10 h.

Example 4 Ferroelectric Nanoparticles

Following the general method given in Examples 1 and 2, for an inorganicprecursor of PbTiO₃, PbTi[OCH(CH₃)₂]₆ (0.2117 g) was utilized as theinorganic precursor-source, and the reaction was refluxed under Ar forabout 2 h. An inorganic precursor source system (BaCl₂.2H₂O+TiCl₄+NaOH)(0.081 g+0.0658 g+0.0139 g) was employed to prepare nanoparticles havinga BaTiO₃ inorganic precursor by refluxing under Ar for about 2 h.

Example 5 Thermoelectric Nanoparticles

Following the general method given in Examples 1 and 2, reaction systems(BiCl₃ (0.1089 g)+Te (0.0443 g)) and (BiCl₃ (0.1089 g)+Se (0.0274 g))were used as the inorganic precursor-source for synthesis of ananomaterial having inorganic precursors of Bi₂Te₃ (0.1 g, yield=71.9%)and Bi₂Se₃ (0.089 g, yield=76.7%), respectively. The reaction wascarried out at 70° C. for about 24 h with NaBH₄ as the reductant andNaOH as the pH-value controller.

Example 6 Upconversion Nanoparticles

Following the general method given in Examples 1 and 2, nanoparticleshaving inorganic precursors of NaYF₄:Tm were prepared by using theinorganic precursor-sources of NaF:YCl₃ (4:1, molar ratio, 0.0583g+0.0677 g) as the host material and TmCl₃ (0.0955 g) as the activator.The reaction system was refluxed under Ar for about 1 h.

Example 7 Superparamagnetic Ion Oxide Nanoparticle (SPION)

Following the general method given in Examples 1 and 2, starting with aninorganic precursor-source of FeCl₂.4H₂O (0.0690 g)+FeCl₃.6H₂O (0.09374g)+ammonium hydroxide (2 mL), nanoparticles with an inorganic precursorof Fe₃O₄ were prepared. The reaction was performed at about 50° C. forabout 30 min, giving nanoparticles including an inorganic precursor ofFe₃O₄ (0.0248 g, yield=92.5%). Similarly, nanoparticles with aninorganic precursor of γ-Fe₂O₃ were produced using ferric(III)acetylacetonate (Fe(acac)₃, 0.1225 g) as the organic precursor-source,and the mixture was refluxed for 2 h, giving nanoparticles with γ-Fe₂O₃as the inorganic precursor source (0.0223 g, yield=80.5%).

Example 8 Semiconductor Nanoparticles

Following the general method given in Examples 1 and 2, a reactionsystem of Cd(acac)₂(0.1078 g)+Se (0.0273 g), TTIP (Ti(OC₃H₇)₄) (0.0986g), (Zn(NO₃).6H₂O (0.1032 g)+KOH (0.0195 g), or copper (I) acetate(CuOAc) (0.0425 g) and SnCl₄.5H₂O (0.1216 g)+hydrochloric acid (0.5 mL)were used as inorganic precursor-source to prepare n-type semiconductornanoparticles having inorganic precursors of CdSe (0.052 g,yield=78.3%), TiO₂ (0.021 g, yield=75.8%), and ZnO (0.019 g,yield=67.3%), or p-type semiconductor nanoparticles having inorganicprecursors of Cu₂O (0.0182 g, yield=73.3%) and SnO (0.0368 g,yield=78.7%), respectively. The reaction systems were refluxed atdifferent times for specific inorganic precursor materials: CdSe forabout 2 h, TiO₂ for about 2 h, ZnO for about 2 h, Cu₂O for about 1 h,and SnO for about 15 h.

The terms and expressions which have been employed are used as terms ofdescription and not of limitation, and there is no intention that in theuse of such terms and expressions of excluding any equivalents of thefeatures shown and described or portions thereof, but it is recognizedthat various modifications are possible within the scope of theinvention claimed. Thus, it should be understood that although thepresent invention has been specifically disclosed by preferredembodiments and optional features, modification and variation of theconcepts herein disclosed may be resorted to by those skilled in theart, and that such modifications and variations are considered to bewithin the scope of this invention as defined by the appended claims.

Additional Embodiments

The present invention provides for the following exemplary embodiments:

Embodiment 1 provides an amphiphilic multi-arm copolymer, including: acore unit; and a plurality of amphiphilic block copolymer arms, whereineach block copolymer arm is substituted on the core unit, wherein eachblock copolymer arm includes at least one hydrophilic homopolymersubunit and at least one hydrophobic homopolymer subunit.

Embodiment 2 provides the amphiphilic multi-arm copolymer of Embodiment1, wherein the core unit includes at least one beta-cyclodextrin unit.

Embodiment 3 provides the amphiphilic multi-arm copolymer of any one ofEmbodiments 1-2, wherein the core unit includes multiplebeta-cyclodextrin units, wherein the multiple beta-cyclodextrin unitsare linked together to form a tubular structure.

Embodiment 4 provides the amphiphilic multi-arm copolymer of any one ofEmbodiments 1-3, wherein the multiple beta-cyclodextrin units are linkedtogether via a plurality of linkages.

Embodiment 5 provides the amphiphilic multi-arm copolymer of any one ofEmbodiments 1-4, wherein the linkages include ethyleneoxy units.

Embodiment 6 provides the amphiphilic multi-arm copolymer of any one ofEmbodiments 1-5, wherein the multi-arm copolymer molecule includes abottlebrush-like block copolymer.

Embodiment 7 provides the amphiphilic multi-arm copolymer of any one ofEmbodiments 1-6, wherein the multi-arm copolymer molecule includes astar-like block copolymer.

Embodiment 8 provides the amphiphilic multi-arm copolymer of any one ofEmbodiments 2-7, wherein the amphiphilic block copolymer arms aresubstituted onto the beta-cyclodextrin unit via oxygen atoms thatinclude hydroxyl groups in an unsubstituted beta-cyclodextrin molecule.

Embodiment 9 provides the amphiphilic multi-arm copolymer of any one ofEmbodiments 2-8, wherein the substitution of the amphiphilic blockcopolymer arm onto the beta-cyclodextrin unit includes substitution of a2,2-dimethylacetyl group on an oxygen atom of the beta-cyclodextrinunit, wherein the oxygen atom includes a hydroxyl group in anunsubstituted beta-cyclodextrin molecule, wherein the at least onehydrophilic homopolymer subunit or the at least one hydrophobichomopolymer subunit of the amphiphilic block copolymer arm is asubstituent at the 2-position of the 2,2-dimethylacetyl group.

Embodiment 10 provides the amphiphilic multi-arm copolymer of any one ofEmbodiments 2-9, wherein the substitution of the amphiphilic blockcopolymer arms onto the beta-cyclodextrin unit includes:

wherein CD-O represents the substituted beta-cyclodextrin unit, Orepresents an oxygen atom that includes a hydroxyl group in anunsubstituted beta-cyclodextrin molecule, and ABC represents the atleast one hydrophilic homopolymer and the at least one hydrophobichomopolymer of the copolymer arm.

Embodiment 11 provides the amphiphilic multi-arm copolymer of any one ofEmbodiments 1-10, wherein the hydrophobic homopolymer subunit isselected from the group consisting of: poly(alkenylaryl) units,poly(alkenylheteroaryl) units, and poly(lactam) units.

Embodiment 12 provides the amphiphilic multi-arm copolymer of any one ofEmbodiments 1-11, wherein the hydrophobic homopolymer subunit isselected from the group consisting of: polystyrene (PS) units,poly(4-vinylpyridine) (P4VP) units, and polycaprolactam (PCL) units.

Embodiment 13 provides the amphiphilic multi-arm copolymer of any one ofEmbodiments 1-12, wherein the hydrophilic homopolymer subunit isselected from the group consisting of: poly(alkyl alkenoate) units,poly(alkenoic acid) units, and poly(alkylene oxide) units.

Embodiment 14 provides the amphiphilic multi-arm copolymer of any one ofEmbodiments 1-13, wherein the hydrophilic homopolymer subunit isselected from the group consisting of: poly(t-butyl acrylate) (PtBA)units, poly(acrylic acid) (PAA) units, and poly(ethylene oxide) (PEO)units.

Embodiment 15 provides the amphiphilic multi-arm copolymer of any one ofEmbodiments 1-14, wherein the amphiphilic block copolymer arms include a2,2-dimethylacetyl group substituted at the 2-position by a blockcopolymer selected from the group consisting of: poly(alkylalkenoate)-b-poly(alkenylaryl), poly(alkylalkenoate)-b-poly(alkenylheteroaryl), poly(alkylalkenoate)-b-poly(lactam), poly(alkenoic acid)-b-poly(alkenylaryl),poly(alkenoic acid)-b-poly(alkenylheteroaryl), poly(alkenoicacid)-b-poly(lactam), poly(alkylene oxide)-b-poly(alkenylaryl),poly(alkylene oxide)-b-poly(alkenylheteroaryl), poly(alkyleneoxide)-b-poly(lactam), poly(alkenylaryl)-b-poly(alkyl alkenoate),poly(alkenylaryl)-b-poly(alkenoic acid),poly(alkenylaryl)-b-poly(alkylene oxide),poly(alkenylheteroaryl)-b-poly(alkyl alkenoate),poly(alkenylheteroaryl)-b-poly(alkenoic acid),poly(alkenylheteroaryl)-b-poly(alkylene oxide),poly(lactam)-b-poly(alkyl alkenoate), poly(lactam)-b-poly(alkenoicacid), and poly(lactam)-b-poly(alkylene oxide).

Embodiment 16 provides the amphiphilic multi-arm copolymer of any one ofEmbodiments 1-15, wherein the amphiphilic block copolymer arms include a2,2-dimethylacetyl group substituted at the 2-position by a blockcopolymer selected from the group consisting of: PtBA-b-PA, PtBA-b-P4VP,PtBA-b-PCL, PAA-b-PS, PAA-b-P4VP, PAA-b-PCL, PEO-b-PS, PEO-b-P4VP,PEO-b-PCL, PS-b-PtBA, PS-b-PAA, PS-b-PEO, P4VP-b-PtBA, P4VP-b-PAA,P4VP-b-PEO, PCL-b-PtBA, PCL-b-PAA, and PCL-b-PEO.

Embodiment 17 provides the amphiphilic multi-arm copolymer of any one ofEmbodiments 1-16, wherein the hydrophilic homopolymer subunits of theamphiphilic block copolymer arms are nearer to the core unit that thehydrophobic homopolymer subunits of the amphiphilic block copolymerarms.

Embodiment 18 provides the amphiphilic multi-arm copolymer of any one ofEmbodiments 1-17, wherein the hydrophobic homopolymer subunits of theamphiphilic block copolymer arms are nearer to the core unit than thehydrophilic homopolymer subunits of the amphiphilic block copolymerarms.

Embodiment 19 provides a nanomaterial, including the amphiphilicmulti-arm copolymer of any one of Embodiments 1-18, further including:at least one inorganic precursor, wherein the inorganic precursor iscoordinated to at least one homopolymer subunit of one of theamphiphilic block copolymer arms.

Embodiment 20 provides the nanomaterial of Embodiment 19, wherein theinorganic precursor is coordinated to at least one homopolymer subunitof each of more than one of the amphiphilic block copolymer arms.

Embodiment 21 provides the nanomaterial of any one of Embodiments 19-20,wherein the amphiphilic block copolymer includes at least oneamphiphilic block copolymer arm having at least one PAA or P4VPhomopolymer subunit, wherein the inorganic precursor is coordinated toat least one of the PAA or P4VP homopolymer subunits.

Embodiment 22 provides the nanomaterial of any one of Embodiments 19-21,wherein the amphiphilic block copolymer includes at least oneamphiphilic block copolymer arm having at least one polyacrylic acidhomopolymer subunit, wherein the inorganic precursor is coordinated tothe polyacrylic acid homopolymer subunit.

Embodiment 23 provides the nanomaterial of any one of Embodiments 19-22,wherein the inorganic precursor is selected from the group consistingof: Au or ions thereof, Ag or ions thereof, PbTiO₃, BaTiO₃, BaSe₃,NaYF₄:Tm, Fe₃O₄ and γ-Fe₂O₃, CdSe, TiO₂, ZnO, Cu₂O, or SnO₂.

Embodiment 24 provides the nanomaterial of any one of Embodiments 19-23,wherein the nanomaterial includes: a nanoparticle, a hollownanoparticle, a core/shell nanoparticle, a nanotube, or a nanorod.

Embodiment 25 provides the nanomaterial of any one of Embodiments 19-24,wherein the nanomaterial includes a Janus nanomaterial.

Embodiment 26 provides a nanomaterial, including a nanomaterial derivedfrom the nanomaterial of any one of Embodiments 19-25.

Embodiment 27 provides a method of making an amphiphilic multi-armcopolymer, including: providing a core that includes hydroxyl functionalgroups; contacting the core with a halogenated esterification reagent,to give a macro-initiator core that includes the core with at least someof the hydroxyl functional groups esterified by the halogenatedesterification reagent; contacting the macro-initiator core with a firsthomopolymer subunit precursor, to give a first substituted coreincluding the macro-initiator core wherein at least one halogen atom isreplaced with a first homopolymer including subunits that include areaction product of the first homopolymer subunit precursor; andcontacting the first substituted core with a second homopolymer subunitprecursor, wherein the second homopolymer subunit precursor is differentthan the first homopolymer subunit precursor, to give a secondsubstituted core including the first substituted core wherein the firsthomopolymer is substituted with a second homopolymer that includessubunits that include a reaction product of the second homopolymersubunit precursor; wherein the first and second homopolymer togetherinclude an amphiphilic block copolymer.

Embodiment 28 provides the method of Embodiment 27, further including:contacting the second substituted core with a third homopolymer subunitprecursor, wherein the third homopolymer subunit precursor is differentthan the second homopolymer precursor, to give a third substituted coreincluding the second substituted core wherein the second homopolymer issubstituted with a third homopolymer that includes subunits that includea reaction product of the third homopolymer subunit precursor.

Embodiment 29 provides the method of any one of Embodiments 27-28,wherein the core includes beta-cyclodextrin.

Embodiment 30 provides the method of any one of Embodiments 27-29,wherein the halogenated esterification reagent includes2-bromoisobutyryl bromide.

Embodiment 31 provides the method of any one of Embodiments 27-30,wherein the first or second homopolymer subunit precursor includes analkyl alkenoate, an alkenoic acid, an alkylene glycol, a alkenylarylcompound, an alkenylheteroaryl compound, or a lactam.

Embodiment 32 provides the method of any one of Embodiments 27-31,wherein the first or second homopolymer subunit precursor includest-butyl acrylate, acrylic acid, ethylene glycol, styrene,4-vinylpyridine, or caprolactam.

Embodiment 33 provides a method of making a nanomaterial, including:contacting the amphiphilic multi-arm copolymer of any one of Embodiments1-18 with an inorganic precursor, to form a nanomaterial that includesthe amphiphilic multi-arm copolymer coordinated to the inorganicprecursor.

Embodiment 34 provides a method of making a nanomaterial, including themethod of any one of Embodiments 27-33, further including: contactingthe amphiphilic multi-arm copolymer with an inorganic precursor, to forma nanomaterial that includes the amphiphilic multi-arm copolymercoordinated to the inorganic precursor.

Embodiment 35 provides the method of Embodiment 34, wherein theinorganic precursor is selected from the group consisting of: Au or ionsthereof, Ag or ions thereof, PbTiO₃, BaTiO₃, BaSe₃, NaYF₄:Tm, Fe₃O₄ andγ-Fe₂O₃, CdSe, TiO₂, ZnO, Cu₂O, or SnO₂.

Embodiment 36 provides the method of any one of Embodiments 34-35,wherein the inorganic precursor is provided by an inorganicprecursor-source.

Embodiment 37 provides the apparatus or method of any one or anycombination of Embodiments 1-36 such that all elements or optionsrecited are available to use or select from.

We claim:
 1. An amphiphilic multi-arm copolymer, comprising: a core unitcomprising at least one beta-cyclodextrin unit; and a plurality ofamphiphilic block copolymer arms each comprising at least onehydrophilic homopolymer subunit and at least one hydrophobic homopolymersubunit, wherein at least one of the hydrophilic homopolymer subunits ofthe amphiphilic block copolymer arm is a substituent at the 2-positionof a 2,2-dimethylacetyl group substituted on an oxygen atom of thebeta-cyclodextrin unit, wherein the oxygen atom corresponds to ahydroxyl group in an unsubstituted beta-cyclodextrin molecule, whereinthe hydrophilic homopolymer subunit is selected from the groupconsisting of poly(alkenoic acid) units and poly(alkylene oxide) units.2. The amphiphilic multi-arm copolymer of claim 1, wherein the core unitcomprises multiple beta-cyclodextrin units linked together in a tubularstructure.
 3. The amphiphilic multi-arm copolymer of claim 2, whereinthe multiple beta-cyclodextrin units are linked together via a pluralityof linkages.
 4. The amphiphilic multi-arm copolymer of claim 2, whereinthe linkages comprise ethyleneoxy units.
 5. The amphiphilic multi-armcopolymer of claim 1, wherein the multi-arm copolymer molecule comprisesat least one of a bottlebrush-like block copolymer and a star-like blockcopolymer.
 6. The amphiphilic multi-arm copolymer of claim 1, whereinthe substitution of the amphiphilic block copolymer arms onto thebeta-cyclodextrin unit comprises:

wherein CD-O represents the substituted beta-cyclodextrin unit, Orepresents an oxygen atom that comprises a hydroxyl group in anunsubstituted beta-cyclodextrin molecule, and ABC represents the atleast one hydrophilic homopolymer and the at least one hydrophobichomopolymer of the copolymer arm.
 7. The amphiphilic multi-arm copolymerof claim 1, wherein the hydrophobic homopolymer subunit is selected fromthe group consisting of: poly(alkenylaryl) units,poly(alkenylheteroaryl) units, and poly(lactam) units.
 8. Theamphiphilic multi-arm copolymer of claim 1, wherein the hydrophobichomopolymer subunit is selected from the group consisting of:polystyrene (PS) units, poly(4-vinylpyridine) (P4VP) units, andpolycaprolactam (PCL) units.
 9. The amphiphilic multi-arm copolymer ofclaim 1, wherein the hydrophilic homopolymer subunit is selected fromthe group consisting of: poly(acrylic acid) (PAA) units andpoly(ethylene oxide) (PEO) units.
 10. The amphiphilic multi-armcopolymer of claim 1, wherein the amphiphilic block copolymer armscomprise a 2,2-dimethylacetyl group substituted at the 2-position by ablock copolymer selected from the group consisting of: poly(alkenoicacid)-b-poly(alkenylaryl), poly(alkenoicacid)-b-poly(alkenylheteroaryl), poly(alkenoic acid)-b-poly(lactam),poly(alkylene oxide)-b-poly(alkenylaryl), poly(alkyleneoxide)-b-poly(alkenylheteroaryl), and poly(alkyleneoxide)-b-poly(lactam).
 11. The amphiphilic multi-arm copolymer of claim1, wherein the amphiphilic block copolymer arms comprise a2,2-dimethylacetyl group substituted at the 2-position by a blockcopolymer selected from the group consisting of: PAA-b-PS, PAA-b-P4VP,PAA-b-PCL, PEO-b-PS, PEO-b-P4VP, and PEO-b-PCL.
 12. A method of makingan amphiphilic multi-arm copolymer, comprising: providing a corecomprising at least one beta-cyclodextrin unit that comprises hydroxylfunctional groups; contacting the core with a halogenated esterificationreagent, to give a macro-initiator core that comprises the core with atleast some of the hydroxyl functional groups esterified by thehalogenated esterification reagent; contacting the macro-initiator corewith a first homopolymer subunit precursor, to give a first substitutedcore comprising the macro-initiator core wherein at least one halogenatom is replaced with a first homopolymer comprising subunits thatcomprise a reaction product of the first homopolymer subunit precursor;and contacting the first substituted core with a second homopolymersubunit precursor, wherein the second homopolymer subunit precursor isdifferent than the first homopolymer subunit precursor, to give a secondsubstituted core comprising the first substituted core wherein the firsthomopolymer is substituted with a second homopolymer that comprisessubunits that comprise a reaction product of the second homopolymersubunit precursor, to give an amphiphilic multi-arm copolymer comprisinga core unit comprising the at least one beta-cyclodextrin unit; and aplurality of amphiphilic block copolymer arms each comprising at leastone hydrophilic homopolymer subunit and at least one hydrophobichomopolymer subunit, wherein at least one of the hydrophilic homopolymersubunits of the amphiphilic block copolymer arm is a substituent at the2-position of a 2,2-dimethylacetyl group substituted on an oxygen atomof the beta-cyclodextrin unit, wherein the oxygen atom corresponds toone of the hydroxyl functional groups in the core prior to thecontacting with the halogenated esterification reagent, wherein thehydrophilic homopolymer subunit is selected from the group consisting ofpoly(alkenoic acid) units and poly(alkylene oxide) units.
 13. The methodof claim 12, further comprising: contacting the second substituted corewith a third homopolymer subunit precursor, wherein the thirdhomopolymer subunit precursor is different than the second homopolymerprecursor, to give a third substituted core comprising the secondsubstituted core wherein the second homopolymer is substituted with athird homopolymer that comprises subunits that comprise a reactionproduct of the third homopolymer subunit precursor.
 14. A method ofmaking a nanomaterial, comprising the method of claim 13, furthercomprising: contacting the amphiphilic multi-arm copolymer with aninorganic precursor, to form a nanomaterial that comprises theamphiphilic multi-arm copolymer coordinated to the inorganic precursor.